I read this today and found it interesting. The key take away point...the way they measure "EF" (energy factor) for hot water heaters is very unreaslistic. So if you think you're purchasing a tankless hot water heater that is has an EF of 0.95...you may be in for a surprise as real world measurements have shown this to range between 0.62 and 0.89.
http://www.greenbuildingadvisor.com/blogs/dept/musings/are-tankless-water-heaters-waste-money
Here's a link to the published data too:
http://www.mncee.org/getattachment/7b8982e9-4d95-4bc9-8e64-f89033617f37/
Wednesday, May 23, 2012
Thursday, May 17, 2012
April Bill
Hey all-
The April Duke Energy Bill just got in...results are posted below:
April 2011
Total KWH = 593
# of Days = 29
Avg consumption = 20.45 kWh/d
April 2012 (4/3-5/2/2012)
Total KWH = 609
# of Days = 29
Avg Consumption = 21.0 kWh/d
Savings versus 2011 = -2.7%
No...that's not a typo folks. I actually used nearly an indentical amount of power this year as last year. Seriously...what are the odds of that? I guess I'm consistent! My gut says that cold spell in April is probably to blame...for 2 days morning temperatures got down to the low 30s which required us to turn on the heat.
FYI, I'm sure you may have noticed that blog has some updates (size and data). I'm just getting it all setup for the eventually addition of the "Live Power Usage", per my previous post. We're almost there...we just need to get through a couple more kinks.
The April Duke Energy Bill just got in...results are posted below:
April 2011
Total KWH = 593
# of Days = 29
Avg consumption = 20.45 kWh/d
April 2012 (4/3-5/2/2012)
Total KWH = 609
# of Days = 29
Avg Consumption = 21.0 kWh/d
Savings versus 2011 = -2.7%
No...that's not a typo folks. I actually used nearly an indentical amount of power this year as last year. Seriously...what are the odds of that? I guess I'm consistent! My gut says that cold spell in April is probably to blame...for 2 days morning temperatures got down to the low 30s which required us to turn on the heat.
FYI, I'm sure you may have noticed that blog has some updates (size and data). I'm just getting it all setup for the eventually addition of the "Live Power Usage", per my previous post. We're almost there...we just need to get through a couple more kinks.
Tuesday, May 8, 2012
Publishing TED Data
Sorry I've been away. We've been working hard on try to create a system to automatically download all my TED data into a Google document and then post it to my blog. Cool stuff huh? Below is an example of me trying it out...
Eventually I'll be creating some graphs and those will be posted hopefully in a sidebar. So if you come back and you see some funky stuff...well...we're in beta testing, so bear with me, OK?
The April measurements will be coming out soon! I don't think we did as well as last year due to that one very chilly week we had (we had freeze warnings!)
Eventually I'll be creating some graphs and those will be posted hopefully in a sidebar. So if you come back and you see some funky stuff...well...we're in beta testing, so bear with me, OK?
The April measurements will be coming out soon! I don't think we did as well as last year due to that one very chilly week we had (we had freeze warnings!)
Saturday, April 14, 2012
March Energy Bills
Last Months bills are in and the results are below:
March 2011
Energy Usage = 984 Kwh
33 Days
Usage= 29.8 Kwh/D
March 2012
Energy Usage= 704 Kwh
32 Days
Daily Usage = 22 Kwh/D
26.2% Reduction
Great, huh? Even with the geothermal, we had a 26% reduction. I'm Chalking that up to the unusually warm season we've had so far. Next month will be interesting as we've needed to use the heat 2x (now 3 as my wife reaches for the thermostat...64 is Ok right?) due to the last 3 chilly nights (30 s!)
March 2011
Energy Usage = 984 Kwh
33 Days
Usage= 29.8 Kwh/D
March 2012
Energy Usage= 704 Kwh
32 Days
Daily Usage = 22 Kwh/D
26.2% Reduction
Great, huh? Even with the geothermal, we had a 26% reduction. I'm Chalking that up to the unusually warm season we've had so far. Next month will be interesting as we've needed to use the heat 2x (now 3 as my wife reaches for the thermostat...64 is Ok right?) due to the last 3 chilly nights (30 s!)
Tuesday, March 27, 2012
Solar Panels - Got a quote - Do I? Or Don't I?
OK...so this afternoon I met up with Greenspring Energy to discuss the idea of putting up solar panels on the roof. I don't have much area...about 215 sf, by my estimate...so the system would not be large.
Anyhow, so this is the system sizing they came up with:
DC size: 2 kW
AC/DC de-rating factor: 0.93
AC rating: 1.9 kW
Type of Panel: Sunpower E20/327 panels
(E20 = 20.1% efficiency; 327W)
# of Panels (@~61.5" x 21.2"): 6
Expected annual output: 3194 kWh (based on PVwatts with an annual average solar rating of 5.07 kWh/m2/day).
Expected annual energy value: $329 assuming 0.103/kWh
Estimated Price: $12,262
Subtotal minus 30% federal and 35% state tax credits: $4,293
Estimated ROI without any increase in dook Energy rates: 13 years
Estimated ROI with a 5%/yr increase in dook Energy rates: 10.5 years
If I do the buy-all sell-all option, the ROI ends up being the same even at the higher $0.15/kWh due to the increase dook Energy monthly "facilities charge" of $16 vs the current $9/month. Leave it to dook energy to spoil all the fun. So, net metering would probably be the best option.
The system would produce roughly 28% of my annual power usage:
Feb 2011 - Feb 2012: 11,470 kWh or 947 kWh/month
Solar PV as % of Household usage: 3194/11470 = 27.8%
On some months the PV would account to roughly 54% of my usage (May-June) while during January it would only be 17% of my bill.
Overall...I'm not too thrilled about their ROI. Having an ROI of 10-13 years is too high. Plus, I know I won't get my state tax credits until at least 2014 because the State still owes me the second half of my geothermal tax credit.
What's interesting is that when I use the solar-estimator.org site, I get a 6 yr ROI. I notice that the solar calculator includes the Duke Energy RECs ($82/yr) and the NC Greenpower incentive ($264/yr)....both of which are not included in Greenspring Energy's calculations. The solar estimator also only has a 3.78% dook energy annaul inflation rate vs their 5%. The ROI goes to 7 years if I set the inflation rate to zero and then set the electricity rate to 0.0929/kWh. While it's not 1-2 years (like my latest mortgage Refinance)...6-7 years is still a pretty good ROI.
So...what do y'all think? My gut says I should at least wait until Fall 2013 for the tax credits...that's assuming the tax credits survive the upcoming election...to minimize the amount of time I have to wait for the tax credit return.
Also...solar technology is evolving quickly. New multi-junction concentrated solar panels are achieving 30-40% efficiencies: http://cleantechnica.com/2011/02/17/high-efficiency-solar-cells-getting-more-efficient-cheaper/
Who knows...in a year these bad-boys could be selling thus allowing me to get even more power from my small roof area (yes...most likely at a premium price...but if the ROI is right...)
Anyhow, so this is the system sizing they came up with:
DC size: 2 kW
AC/DC de-rating factor: 0.93
AC rating: 1.9 kW
Type of Panel: Sunpower E20/327 panels
(E20 = 20.1% efficiency; 327W)
# of Panels (@~61.5" x 21.2"): 6
Expected annual output: 3194 kWh (based on PVwatts with an annual average solar rating of 5.07 kWh/m2/day).
Expected annual energy value: $329 assuming 0.103/kWh
Estimated Price: $12,262
Subtotal minus 30% federal and 35% state tax credits: $4,293
Estimated ROI without any increase in dook Energy rates: 13 years
Estimated ROI with a 5%/yr increase in dook Energy rates: 10.5 years
If I do the buy-all sell-all option, the ROI ends up being the same even at the higher $0.15/kWh due to the increase dook Energy monthly "facilities charge" of $16 vs the current $9/month. Leave it to dook energy to spoil all the fun. So, net metering would probably be the best option.
The system would produce roughly 28% of my annual power usage:
Feb 2011 - Feb 2012: 11,470 kWh or 947 kWh/month
Solar PV as % of Household usage: 3194/11470 = 27.8%
On some months the PV would account to roughly 54% of my usage (May-June) while during January it would only be 17% of my bill.
Overall...I'm not too thrilled about their ROI. Having an ROI of 10-13 years is too high. Plus, I know I won't get my state tax credits until at least 2014 because the State still owes me the second half of my geothermal tax credit.
What's interesting is that when I use the solar-estimator.org site, I get a 6 yr ROI. I notice that the solar calculator includes the Duke Energy RECs ($82/yr) and the NC Greenpower incentive ($264/yr)....both of which are not included in Greenspring Energy's calculations. The solar estimator also only has a 3.78% dook energy annaul inflation rate vs their 5%. The ROI goes to 7 years if I set the inflation rate to zero and then set the electricity rate to 0.0929/kWh. While it's not 1-2 years (like my latest mortgage Refinance)...6-7 years is still a pretty good ROI.
So...what do y'all think? My gut says I should at least wait until Fall 2013 for the tax credits...that's assuming the tax credits survive the upcoming election...to minimize the amount of time I have to wait for the tax credit return.
Also...solar technology is evolving quickly. New multi-junction concentrated solar panels are achieving 30-40% efficiencies: http://cleantechnica.com/2011/02/17/high-efficiency-solar-cells-getting-more-efficient-cheaper/
Who knows...in a year these bad-boys could be selling thus allowing me to get even more power from my small roof area (yes...most likely at a premium price...but if the ROI is right...)
March Bill ~40% reduction in energy use
OK OK OK....yes I've been slacking. And by slacking...yeah, it's been a LOT. There's no good excuse for me, so sorry!
I will say that ever since we switched to e-billing, I don't get to see the bill when it comes...so I have to bug my wife to let me know what it says. So there...ha! I can somewhat blame my unresponsiveness on her, right?
We got March's bill on the 6th and here's the results:
March 2011 Bill - 953 kWh over 28 days or 34.04 kWh/d
March 2011 Natural Gas Bill- 24 CCF over 28 days or 0.857 CCF/d -->converted--> 25.9 kWh/d
Total March 2011 = 59.91 kWh/d
March 2012 Bill = 1051 kWh over 29 days = 36.24 kWh/d
% Savings = 39.51%
Comparison to March 2010 (Townhome) = 71.10 kWh/day
% Savings = 49%
So the savings keep adding up. Since March 2010 was when we first moved into our new home, the comparison against the Townhome is over. On average the Geothermal system has reduced my energy consumption enough (in the 2700 sf single family house) such that our energy usage is ~16% less than the former 1300 sf townhouse. That's pretty cool.
Money wise its not as significant thanks to the latest Duke Energy increase in rates. But it could be worse, that's for sure. Below is how our total energy bill has compared. I like the fact that our bills are much more reasonable (again...the April Bill is just an extrapolation of the TED data). Since installing the geothermal, our largest bill was the January bill (aka dated in January...but actually for December).
I guess now the question is...what do I do next?
I certainly do plan on installing a new HW heater in series with my existing to optimize the Geothermal dessuperheater. Eventually I'm going to add in a Nyle Geyser ASHP to the new HW heater.
And today, I'm meeting with Green Spring Energy to talk about solar panels. That'll be a discussion on another post...maybe tomorrow?
I will say that ever since we switched to e-billing, I don't get to see the bill when it comes...so I have to bug my wife to let me know what it says. So there...ha! I can somewhat blame my unresponsiveness on her, right?
We got March's bill on the 6th and here's the results:
March 2011 Bill - 953 kWh over 28 days or 34.04 kWh/d
March 2011 Natural Gas Bill- 24 CCF over 28 days or 0.857 CCF/d -->converted--> 25.9 kWh/d
Total March 2011 = 59.91 kWh/d
March 2012 Bill = 1051 kWh over 29 days = 36.24 kWh/d
% Savings = 39.51%
Comparison to March 2010 (Townhome) = 71.10 kWh/day
% Savings = 49%
So the savings keep adding up. Since March 2010 was when we first moved into our new home, the comparison against the Townhome is over. On average the Geothermal system has reduced my energy consumption enough (in the 2700 sf single family house) such that our energy usage is ~16% less than the former 1300 sf townhouse. That's pretty cool.
Below is a figure showing our home energy usage from when we moved in to date (Note: April 2012 is just an extrapolation from the TED data to date). You can see that our energy usage used to varied greatly with the seasons especially in the summer and winter. Afte we did all our housework and installed the Geothermal system our energy usage is significantly lower...one average 33%...and it would be higher except that during the spring and fall (like what we're doing now), we turn off our HVAC system because the house stays comfy day and night with simply opening up the windows.
I guess now the question is...what do I do next?
I certainly do plan on installing a new HW heater in series with my existing to optimize the Geothermal dessuperheater. Eventually I'm going to add in a Nyle Geyser ASHP to the new HW heater.
And today, I'm meeting with Green Spring Energy to talk about solar panels. That'll be a discussion on another post...maybe tomorrow?
Saturday, February 11, 2012
February Bill - 64% reduction
We got the Duke Energy Bill for February a couple days ago...drum-roll please:
Feb 2011 Electricity Bill: 1967 kWh
Number of days: 28
Average: 70.25 kWh/d
Natural Gas Usage: 19 CCF (108,722 BTU/d) = 31.9 kWh/d
Total 2011 Usage: 102.11 kWh/d
Feb 2012 Electricity Bill: 1075 kWh/d
Number of days: 29
Average: 37.1 kWh/d
Savings = 63.7%
Comparison to the former townhome: 51.1% reduction
I'm not celebrating too much. Last month was unusually warm here...not to say that we didn't have our cool nights...but still...some days were in the high 60s/low 70s.
Savings are savings, right? I'll take it...
Feb 2011 Electricity Bill: 1967 kWh
Number of days: 28
Average: 70.25 kWh/d
Natural Gas Usage: 19 CCF (108,722 BTU/d) = 31.9 kWh/d
Total 2011 Usage: 102.11 kWh/d
Feb 2012 Electricity Bill: 1075 kWh/d
Number of days: 29
Average: 37.1 kWh/d
Savings = 63.7%
Comparison to the former townhome: 51.1% reduction
I'm not celebrating too much. Last month was unusually warm here...not to say that we didn't have our cool nights...but still...some days were in the high 60s/low 70s.
Savings are savings, right? I'll take it...
Thursday, January 19, 2012
Electric Hot Water? Or switch to gas?
So I was looking at the newspaper the other day and noticed that my local utility, Piedmont Natural Gas, has just asked the NC State Utilities Commission to lower their rates by 5%. This is after Duke Energy initially wanted a 17% hike in electricity rates...which the Utility Commission wants to limit them to 7%. Either way...Electricity Up...Natural gas down.
This has made me think about my stance on natural gas hot water. As I've written previously...I'd like to keep my future in my own hands. I can't make natural gas (ok...maybe a little after a nigh drinking microbrews or my wife's chili...) but I can make my own electricity via solar panels. And I hope to do so one day. However, the fact that natural gas is getting cheaper is intriguing.
As of now, I'm using my hot water heater roughly 0.75 hrs per day....note that it is winter here. So that's equal to ~3.6 kWh/d or $0.306/day @ $0.085/kWh (note...this rate is current and doesn't include the projected increase).
Natural gas has a heating value of 1000 BTU/ft3 (it varies, but let's use this for simplicity). And there's 3415.18 BTU/hr in a kW. So if I assume a regular gas hot water heater with 67% efficiency, then I'd be using:
3.6 kWh * 3415.18 BTU/1 kW-hr * 1 ft3/1000 BTU * 1/0.67 = 18.35 ft3 of natural gas.
Since I pay in therms I need to convert it (100 ft3 = 1 therm): 18.35 ft3/100 ft3 = 0.1835 therms.
The current cost for natural gas is $0.95208/therm. So...this equals $0.175/day which is roughly half of what I'm paying now using electricity. If I get a high efficiency condensing gas hot water heater, then the efficiency jumps to 95-97%...let's say 92% to be conservative. The revised cost is:
3.6 kWh * 3415.18 BTU/1 kW-hr * 1 ft3/1000 BTU * 1/0.92 * 1 therm/100 ft3 * $0.95208/therm = $0.127/day
This is a 27% reduction in the daily cost. Fantastic, right?
Now...one thing to factor in is that I'd have to pay a crappy "monthly charge" of $10/mo. That's right folks...$10/mo to have the honor of being a customer. Yes...I do pay a similar charge to be an electricty customer...but I can't turn off my electricty now can I?
I'll leave that be...
So the $10/mo over 30 days = $0.333 per day. So my daily cost is now $0.46/day (using the high efficiency gas unit). Could I use natural gas somewhere else? I guess so...I could switch my cooktop over to gas. And then there's my grill...natural gas certainly is cheaper than propane. I'd have to buy one of those $50 conversion kits though.
If I look back at my former townhome (we had natural gas hot water, heating, and cooktop...we had an electric oven), during the summer months we used about 7.5 therms per month (June through October 2009). So no heating...this is just hot water and cooking. And we should asterisk the hot water since I know I don't take long hot showers in the summer.
Anyway...7.5 therms/month = $7.14/mo. or $0.238 per day. Add in the monthly charge and I'm at $0.571 per day.
If I recall, my electric cooktop uses about 3 kW. It varies depending on which burner is uses...yadda yadda. Cooking generally doesn't take more than 30 minutes. But let's say an hour/day assuming I finally get my butt cooking more. 3 kWh is $0.255...so adding that in, I'm now at $0.561/day.
Given that I highly doubt I'll ever be cooking on average 1 hr/day every day, I gotta call this for electricty...at current rates.
What does this all mean? Well...it means I really need to think about what to do about the hot water heater and maybe get some consulting from my buddies. While gas would be nice...its tough to justify.
Any thoughts out there? Did I miss something? Yes...there's non-quantitative benefits that I've excluded for now...
This has made me think about my stance on natural gas hot water. As I've written previously...I'd like to keep my future in my own hands. I can't make natural gas (ok...maybe a little after a nigh drinking microbrews or my wife's chili...) but I can make my own electricity via solar panels. And I hope to do so one day. However, the fact that natural gas is getting cheaper is intriguing.
As of now, I'm using my hot water heater roughly 0.75 hrs per day....note that it is winter here. So that's equal to ~3.6 kWh/d or $0.306/day @ $0.085/kWh (note...this rate is current and doesn't include the projected increase).
Natural gas has a heating value of 1000 BTU/ft3 (it varies, but let's use this for simplicity). And there's 3415.18 BTU/hr in a kW. So if I assume a regular gas hot water heater with 67% efficiency, then I'd be using:
3.6 kWh * 3415.18 BTU/1 kW-hr * 1 ft3/1000 BTU * 1/0.67 = 18.35 ft3 of natural gas.
Since I pay in therms I need to convert it (100 ft3 = 1 therm): 18.35 ft3/100 ft3 = 0.1835 therms.
The current cost for natural gas is $0.95208/therm. So...this equals $0.175/day which is roughly half of what I'm paying now using electricity. If I get a high efficiency condensing gas hot water heater, then the efficiency jumps to 95-97%...let's say 92% to be conservative. The revised cost is:
3.6 kWh * 3415.18 BTU/1 kW-hr * 1 ft3/1000 BTU * 1/0.92 * 1 therm/100 ft3 * $0.95208/therm = $0.127/day
This is a 27% reduction in the daily cost. Fantastic, right?
Now...one thing to factor in is that I'd have to pay a crappy "monthly charge" of $10/mo. That's right folks...$10/mo to have the honor of being a customer. Yes...I do pay a similar charge to be an electricty customer...but I can't turn off my electricty now can I?
I'll leave that be...
So the $10/mo over 30 days = $0.333 per day. So my daily cost is now $0.46/day (using the high efficiency gas unit). Could I use natural gas somewhere else? I guess so...I could switch my cooktop over to gas. And then there's my grill...natural gas certainly is cheaper than propane. I'd have to buy one of those $50 conversion kits though.
If I look back at my former townhome (we had natural gas hot water, heating, and cooktop...we had an electric oven), during the summer months we used about 7.5 therms per month (June through October 2009). So no heating...this is just hot water and cooking. And we should asterisk the hot water since I know I don't take long hot showers in the summer.
Anyway...7.5 therms/month = $7.14/mo. or $0.238 per day. Add in the monthly charge and I'm at $0.571 per day.
If I recall, my electric cooktop uses about 3 kW. It varies depending on which burner is uses...yadda yadda. Cooking generally doesn't take more than 30 minutes. But let's say an hour/day assuming I finally get my butt cooking more. 3 kWh is $0.255...so adding that in, I'm now at $0.561/day.
Given that I highly doubt I'll ever be cooking on average 1 hr/day every day, I gotta call this for electricty...at current rates.
What does this all mean? Well...it means I really need to think about what to do about the hot water heater and maybe get some consulting from my buddies. While gas would be nice...its tough to justify.
Any thoughts out there? Did I miss something? Yes...there's non-quantitative benefits that I've excluded for now...
Sunday, January 15, 2012
January Energy Bill - 58% REDUCTION
Well...I've been waiting for this bill for a while and it finally arrived. It was a little unusual this time because my wife changed to an ebill so my daily walk to the mailbox was not there...but that's another story. So let's just see the results:
January 2011 Energy Usage: 3,224 kWh over 34 days = 94.8 kWh/d
January 2011 Bill = $253
January 2012 Energy Usage: 1,318 kWh over 33 days = 39.9 kWh/d
January 2012 Bill = $121
Reduction in Energy Usage = 57.9%
Savings on Bill = $132
Comparing to former 2009 1300sf townhome:
January Energy Usage = 70.99 kWh/d or a 44% reduction in energy usage
Ohhh yeah! As I've said in the past, heating is where the Geothermal system really shines. And its proven with the 58% reduction! This is right in line where I thought we'd be (estimating between 50 and 67%). And then being 44% under the former townhome (of half the size) is just icing on the cake.
Next month should be another poster month: Feb 2011 = 102.11 KWh/day. That month we used our gas fireplace a lot for heating so our actual electricity bill had only 70.2 kWh/day. Feb 2010 in the Townhome had 75.8 kWh/d.
January 2011 Energy Usage: 3,224 kWh over 34 days = 94.8 kWh/d
January 2011 Bill = $253
January 2012 Energy Usage: 1,318 kWh over 33 days = 39.9 kWh/d
January 2012 Bill = $121
Reduction in Energy Usage = 57.9%
Savings on Bill = $132
Comparing to former 2009 1300sf townhome:
January Energy Usage = 70.99 kWh/d or a 44% reduction in energy usage
Ohhh yeah! As I've said in the past, heating is where the Geothermal system really shines. And its proven with the 58% reduction! This is right in line where I thought we'd be (estimating between 50 and 67%). And then being 44% under the former townhome (of half the size) is just icing on the cake.
Next month should be another poster month: Feb 2011 = 102.11 KWh/day. That month we used our gas fireplace a lot for heating so our actual electricity bill had only 70.2 kWh/day. Feb 2010 in the Townhome had 75.8 kWh/d.
Friday, January 6, 2012
Energy Star Yardstick
So I was searching the 'net (really for homemade storm windows...that's a different story) and I came across the Energy Star "Assess Your Home" website (Click here to check it out). It's a fairly simple...you input where you live, how many folks in the household, the size of the house, and then your annual utility bills (electrical, gas, etc). The key here is annual...you can put in monthly bills, but there has to be 12 months worth.
So I put my information in. The only thing is that I haven't run the Geothermal for a year yet. Nor have I received last months bill. So for my January bill, I used the TED5000 values (which have always been high). And then for the next two months (my system was installed in February 2010), I just used a rough estimate compared to previous years.
To recap...I've used 7,182 kWh over 272 days (9 months) which is 26.4 kWh/day. For last months (arriving any day now) bill, I put in the TED value of 1281 kWh. Then for the next two months I assumed 1,000 kWh and 750 kWh. With those assumptions, that put me at 11,166 kWh/year or 30.6 kWh/day.
Putting in all this information gave me the following:
Yeah...I'm a little excited about getting a 9 out of 10. That's pretty cool....and this is a "normal" house (no superinsulation...no solar panels (yet)....etc) I'm totally going to be interested to see if/how my score changes once I have a full years worth of data in there. What's kind of neat is the "Set your Goal" info at the bottom. I put in an assumed 10% reducation goal (equal to ~1,117 kWh/yr or 3.06 kWh/day) and it said my Score would increase to a 9.4. Well...my next project will most likely be my hot water heater. Currently hot water is using about 3.6 kWh/day (~0.75 hours @ 4.8 kW). So reducing this in half would give me about 1.8 kWh/day of savings. I'm still trying to figure out how to get one of those heat pump models in there which accomplish two goals: (a) I'd have a preheat tank for the geothermal desuperheater to maximize its efficiency and (b) I'd have a high efficiency unit which would be 2.6x more efficienct.
After that...well...I don't know what else to do. I was planning on re-doing my house siding which includes housewrap. That's *supposed* to reduce energy consumption by 10-15%. Then there's solar panels...but those are pretty expensive. Who knows what else after that...any ideas?
So I put my information in. The only thing is that I haven't run the Geothermal for a year yet. Nor have I received last months bill. So for my January bill, I used the TED5000 values (which have always been high). And then for the next two months (my system was installed in February 2010), I just used a rough estimate compared to previous years.
To recap...I've used 7,182 kWh over 272 days (9 months) which is 26.4 kWh/day. For last months (arriving any day now) bill, I put in the TED value of 1281 kWh. Then for the next two months I assumed 1,000 kWh and 750 kWh. With those assumptions, that put me at 11,166 kWh/year or 30.6 kWh/day.
Putting in all this information gave me the following:
After that...well...I don't know what else to do. I was planning on re-doing my house siding which includes housewrap. That's *supposed* to reduce energy consumption by 10-15%. Then there's solar panels...but those are pretty expensive. Who knows what else after that...any ideas?
Thursday, January 5, 2012
UPDATE: Geothermal Aux Heat and Desuperheater
Per my post yesterday I got to work on my HVAC system. I completed the following:
So...what's the results of this? Well this AM was another Brrrr cold AM. It wasn't as cold as yesterday (low of 21F), but it was still fairly cold (31F). TED data shows that I used a lot less energy from 12AM to 10AM:
Jan 4: 26.7 kWh
Jan 5: 20.4 kWh
Savings: 6.3kWh
While I can't say for sure unless I get another identical day, I'd like to think I created some savings. I certainly didn't see the Aux Heat on this AM. But only time will tell....and I'll be watching it like a hawk...hopefully reporting results...
- Increased my minimum "away" temperature to 64F instead of 62F to minimize my temperature rise. It was previously 7F and now its 5F.
- Set both thermostats to 2 cycles per hour (heat and cooling)
- Set the backup heat lockout temperature to 30F (if outside temp is >30F, then the backup heat won't come on, even if called for)
- Set the backup heat droop temperature to 5F (if the system calls for heat and the temperature continues to drop 5F, then the backup heat will be called on)
- I set the upstage timer to 60 minutes. So if the running system cannot meet the temperature setting within 60min, then the next stage will be called on)
- I insulated the desuperheater piping (geothermal unit to the HWT).
- I set the thermostats on the HWT. Upper one is set to 120F (no change), lower one is now set to 90F
So...what's the results of this? Well this AM was another Brrrr cold AM. It wasn't as cold as yesterday (low of 21F), but it was still fairly cold (31F). TED data shows that I used a lot less energy from 12AM to 10AM:
Jan 4: 26.7 kWh
Jan 5: 20.4 kWh
Savings: 6.3kWh
While I can't say for sure unless I get another identical day, I'd like to think I created some savings. I certainly didn't see the Aux Heat on this AM. But only time will tell....and I'll be watching it like a hawk...hopefully reporting results...
Wednesday, January 4, 2012
Geothermal, Aux Heat, and Desuperheater
So this AM after my normal morning shower, dressing routine, I almost always go and check the thermostat before going downstairs. I do this because the programmable T-stat lowers the temp automatically at 7am when we're typically done the getting ready routine. If I'm early, then I like to manually lower the temp to save some energy. I had also noticed recently that Stage 2 was running a lot...but I had chalked that up to the cold temperatures outside.
Well, today when I checked the t-stat, I saw the aux heat was on. REALLY?!? WTF?!? (Note: The Aux heat is 5 kW in each unit). Yes...it was cold this AM (20F), but there should be no reason the Geothermal can't handle it. It's not like the system is seeing the 20F. So I quickly lowered the temp to turn off the aux heat and ran downstairs...to find the same thing. The f*#$ aux heat was on! So that's 10 kW of extra electrical demand. Checking my TED 5000 confirmed the aux heat was on for roughly 40 minutes. That's an extra 6.7 kWh added to my bill. And yes...it appears it was on yesterday too.
Extremely pissed off, I went online to see if the thermostat was setup incorrect. I'll tell you what...the instructions on thermostats when it comes to these settings is damn near non-existent. I gave up and went to the T-stat settings (each one) and turned the Back-Heat to "Economy Mode", and turned the "Heat Control Mode" to "Less Aggressive". While there, I did the same for the "Cooling Control Mode". This was kind of arbitrary at the time.
I did some further searching later in the AM. I ended up in the GeoExchange forum finding that most thermostats aren't made for geothermal systems. So their default settings are NOT appropriate. Looking at my settings, the Stage 1 is set to run at 3 cycles per hour (CPH), Stage 2 is 3 CPH, and the Aux heat is 9 CPH. From reading the forums, most people have set the Stage 1/2 to either 1 or 2 CPH which apparently increases efficiency (i.e. allows each Stage to run longer). It's slightly confusing because the lower the number, the better apparently. The definition is:
"cycle rate is the ideal number of times a heating system will run, in an hour, to maintain temperature within one degree. For instance, gas or oil forced air systems have a recommended cycle rate of 6. With a cycle rate of 6, the heating system, at a 50% load, will cycle 6 times per hour. This breaks down to about 5 minutes on and 5 minutes off. Again, the actual on and off time of the heating system will vary as the load on the heating system varies."
So a setting of 3 is 10 minutes on/10 minutes off. And if this is correct, then a setting of 2 is 15 minutes on/off and finally a setting of 1 is 30 minutes on/off. Going with a longer run time allows for more air movement and a more "steady-state" operation.
I found a good explanation of CPH below:
"CPH, is the digital equivalent to the old heat anticipators that actually heated the thermostat.
In Honeywell thermostats its just an algorithm based on previous on and off times, to attempt to maintain an X amount of temp differential/deadband/droop, by increasing or decreasing the on and off times. And is only accurate when the homes heat loss or gain is at 50% of the equipments heating/cooling capacity. The size of the equipment will determine when the thermostat can maintain its set CPH. And as the outdoor temp varies, the actual CPH will also vary, and the duration of the on and the off time will change accordingly with one increasing and the other decreasing.
A thermostat set for 3 CPH, will have a continuous run time when the outdoor temps and indoor set temp are at design conditions, and the heating or cooling equipment is sized for those design conditions. If the outdoor temp rises 5 degrees above outdoor design in winter, even with the CPH set to 6, the system will be cycling at 1.5 or 2 cycles per hour. If it rises another 5 degrees, the stat may begin to have 1 or 2 minute off times, which becomes very annoying and hard on the equipment.
Temp over rides CPH setting. The thermostat continually monitors temp, And recalculates when it should bring on the heat or A/C. And how long it should run it. And then when it brings on the equipment, in monitors the progress and recalculates how long it should keep on running the equipment. Along with how long it should keep it off once it shuts the equipment off. It is constantly recalculating the on and off time by monitoring the temp. Temp over rides CPH setting.
A higher CPH means more on and off times an hour, so the equipment will short cycle. But maintain a very tight temp control of the hose. Very comfortable, but hard on the equipment.
A lower setting will allow a wider temp swing in the house, and be much easier on the equipment. The temp swing increase will only be a few tenths of a degree."
I've seen stuff back and forth on setting the Aux Heat to the same as the heating/cooling...so maybe I'll do that as well. I also found out that with my outdoor temperature sensor, I need to turn on the "Outdoor Temperature Aux Heat Lock Out" which locks out the use of the Aux heat if the temperature is above a specified temperatures setpoint. I've seen numbers flying around but I would think it would make sense for this to be 30F just in case the Geosystem goes down and its below freezing to prevent any water pipes from freezing/breaking. Finally, there's a recommendation to change the delta between Stages 1 and 2 to be 3F so the first stage will run more often. However, my thermostat doesn't have this feature oddly enough....the closest I have is "deadband". There is an upstage timer which I think I could use...but I'd need to check. Increasing the timer means that Stage 1 will run for XXX minutes and then if the timer expires and the temperature has not yet been reached, then Stage 2 will come on, etc. I'll have to play with this that's for sure.
Oh yeah...almost forgot about the desuperheater. In the same forum I came across some folks talking about the desuperheater. Apparently I need to check out my installation. I've talked about it previously, but the most efficienct system uses a pre-heat tank and then the hot water heater (HWH). I don't have this (yet) so I only have my HWH. Well...apparently I need to make sure my upper and lower elements are at different temperatures. So the lower one needs to be set at 100F while the upper is at the normal HW temp...say 120-130F. This is because the desuperheater measures the water temperatures. If its above a setpoint (130F apparently), then it doesn't turn on (it says the HWH is already at temperature...don't bother). Well...I think my lower one is set to 120F and I've never checked my upper one. I know the installers didn't change anything because my HWH has a insulation blanket around it...and to get at the element thermostats you'd need to either remove the blanket or cut a hole. Neither was done beacuse I cut a hole in the blanket to get at the lower element this fall. So I definately need to change these settings! And I was wondering why I didn't feel like I was getting any "free" hot water from the desuperheater...that's because the HWH was maintaining the 120-130F setting and the geothermal system would sense it and say not to use the desuperheater or it would run minimally. Dang it!!!!!! Well...that'll be fixed today. Also, I need to insulate the piping from the HWH to the desuperheater. Looking at pics it doesn't have any insulation on it and I need this to (a) get a good temperature reading and (b) to make sure the heat that it put in is actually making it to the HWH.
Well, today when I checked the t-stat, I saw the aux heat was on. REALLY?!? WTF?!? (Note: The Aux heat is 5 kW in each unit). Yes...it was cold this AM (20F), but there should be no reason the Geothermal can't handle it. It's not like the system is seeing the 20F. So I quickly lowered the temp to turn off the aux heat and ran downstairs...to find the same thing. The f*#$ aux heat was on! So that's 10 kW of extra electrical demand. Checking my TED 5000 confirmed the aux heat was on for roughly 40 minutes. That's an extra 6.7 kWh added to my bill. And yes...it appears it was on yesterday too.
Extremely pissed off, I went online to see if the thermostat was setup incorrect. I'll tell you what...the instructions on thermostats when it comes to these settings is damn near non-existent. I gave up and went to the T-stat settings (each one) and turned the Back-Heat to "Economy Mode", and turned the "Heat Control Mode" to "Less Aggressive". While there, I did the same for the "Cooling Control Mode". This was kind of arbitrary at the time.
I did some further searching later in the AM. I ended up in the GeoExchange forum finding that most thermostats aren't made for geothermal systems. So their default settings are NOT appropriate. Looking at my settings, the Stage 1 is set to run at 3 cycles per hour (CPH), Stage 2 is 3 CPH, and the Aux heat is 9 CPH. From reading the forums, most people have set the Stage 1/2 to either 1 or 2 CPH which apparently increases efficiency (i.e. allows each Stage to run longer). It's slightly confusing because the lower the number, the better apparently. The definition is:
"cycle rate is the ideal number of times a heating system will run, in an hour, to maintain temperature within one degree. For instance, gas or oil forced air systems have a recommended cycle rate of 6. With a cycle rate of 6, the heating system, at a 50% load, will cycle 6 times per hour. This breaks down to about 5 minutes on and 5 minutes off. Again, the actual on and off time of the heating system will vary as the load on the heating system varies."
So a setting of 3 is 10 minutes on/10 minutes off. And if this is correct, then a setting of 2 is 15 minutes on/off and finally a setting of 1 is 30 minutes on/off. Going with a longer run time allows for more air movement and a more "steady-state" operation.
I found a good explanation of CPH below:
"CPH, is the digital equivalent to the old heat anticipators that actually heated the thermostat.
In Honeywell thermostats its just an algorithm based on previous on and off times, to attempt to maintain an X amount of temp differential/deadband/droop, by increasing or decreasing the on and off times. And is only accurate when the homes heat loss or gain is at 50% of the equipments heating/cooling capacity. The size of the equipment will determine when the thermostat can maintain its set CPH. And as the outdoor temp varies, the actual CPH will also vary, and the duration of the on and the off time will change accordingly with one increasing and the other decreasing.
A thermostat set for 3 CPH, will have a continuous run time when the outdoor temps and indoor set temp are at design conditions, and the heating or cooling equipment is sized for those design conditions. If the outdoor temp rises 5 degrees above outdoor design in winter, even with the CPH set to 6, the system will be cycling at 1.5 or 2 cycles per hour. If it rises another 5 degrees, the stat may begin to have 1 or 2 minute off times, which becomes very annoying and hard on the equipment.
Temp over rides CPH setting. The thermostat continually monitors temp, And recalculates when it should bring on the heat or A/C. And how long it should run it. And then when it brings on the equipment, in monitors the progress and recalculates how long it should keep on running the equipment. Along with how long it should keep it off once it shuts the equipment off. It is constantly recalculating the on and off time by monitoring the temp. Temp over rides CPH setting.
A higher CPH means more on and off times an hour, so the equipment will short cycle. But maintain a very tight temp control of the hose. Very comfortable, but hard on the equipment.
A lower setting will allow a wider temp swing in the house, and be much easier on the equipment. The temp swing increase will only be a few tenths of a degree."
I've seen stuff back and forth on setting the Aux Heat to the same as the heating/cooling...so maybe I'll do that as well. I also found out that with my outdoor temperature sensor, I need to turn on the "Outdoor Temperature Aux Heat Lock Out" which locks out the use of the Aux heat if the temperature is above a specified temperatures setpoint. I've seen numbers flying around but I would think it would make sense for this to be 30F just in case the Geosystem goes down and its below freezing to prevent any water pipes from freezing/breaking. Finally, there's a recommendation to change the delta between Stages 1 and 2 to be 3F so the first stage will run more often. However, my thermostat doesn't have this feature oddly enough....the closest I have is "deadband". There is an upstage timer which I think I could use...but I'd need to check. Increasing the timer means that Stage 1 will run for XXX minutes and then if the timer expires and the temperature has not yet been reached, then Stage 2 will come on, etc. I'll have to play with this that's for sure.
Oh yeah...almost forgot about the desuperheater. In the same forum I came across some folks talking about the desuperheater. Apparently I need to check out my installation. I've talked about it previously, but the most efficienct system uses a pre-heat tank and then the hot water heater (HWH). I don't have this (yet) so I only have my HWH. Well...apparently I need to make sure my upper and lower elements are at different temperatures. So the lower one needs to be set at 100F while the upper is at the normal HW temp...say 120-130F. This is because the desuperheater measures the water temperatures. If its above a setpoint (130F apparently), then it doesn't turn on (it says the HWH is already at temperature...don't bother). Well...I think my lower one is set to 120F and I've never checked my upper one. I know the installers didn't change anything because my HWH has a insulation blanket around it...and to get at the element thermostats you'd need to either remove the blanket or cut a hole. Neither was done beacuse I cut a hole in the blanket to get at the lower element this fall. So I definately need to change these settings! And I was wondering why I didn't feel like I was getting any "free" hot water from the desuperheater...that's because the HWH was maintaining the 120-130F setting and the geothermal system would sense it and say not to use the desuperheater or it would run minimally. Dang it!!!!!! Well...that'll be fixed today. Also, I need to insulate the piping from the HWH to the desuperheater. Looking at pics it doesn't have any insulation on it and I need this to (a) get a good temperature reading and (b) to make sure the heat that it put in is actually making it to the HWH.
Saturday, December 17, 2011
Going solar...revisited
Ok...so I wanted to revisit the "going solar...is it worth it" and look at my assumptions. Well...one assumption was the 25% energy usage. If I want to maximize my tax deduction, then I should try to get the largest system for my money because the ROI will follow this assumption. Well...the maximum tax deduction is limited by the NC Renewable Energy Personal Tax Credit. This credit is 35% of the installed cost up to a maximum of $10,500. So...if I want to maximize this then my system would need to cost: $10,500/0.35 = $30,000.
So...if I play with the solar-estimate.org calculator, that means my system could be a maximum of about 3.8 kW or roughly 46% of my estimated average annual electricity usage.
Now what's interesting is that the ROI for the system is highly dependent on how you finance the system. I noticed that the default borrowing is set to 30-years...aka a mortgage. And what's interesting is that the more you borrow...the better the ROI. So if you borrow 50% of the cost (they estimate ~$11,000 after tax credits) at 6.5% over 25-years, then the ROI is 4 years. If you borrow 100%, then the ROI is zero years. Why is this? Well...the annual loan payment is less than the sum of the utility savings+NC Greenpower incentives + Duke Energy RECs. As the loan life shortens to say, 5 years, then the ROI creeps up to 10 years.
So essentially what this is says...is if you can refinance your home or purchase your home with some extra cash for the upgrade and put on a solar system, then you'll be golden with zero to one year ROI. The best loan terms I could find were 15 years loans on Home Equity. Other than that most loans are limited to 5 years.
Of course, as my wife says....this is all dependent on if you can even put this on your roof. Who knows what our homeowners association would say about the panels. Lots of folks out there can be ignorant...
So...if I play with the solar-estimate.org calculator, that means my system could be a maximum of about 3.8 kW or roughly 46% of my estimated average annual electricity usage.
Now what's interesting is that the ROI for the system is highly dependent on how you finance the system. I noticed that the default borrowing is set to 30-years...aka a mortgage. And what's interesting is that the more you borrow...the better the ROI. So if you borrow 50% of the cost (they estimate ~$11,000 after tax credits) at 6.5% over 25-years, then the ROI is 4 years. If you borrow 100%, then the ROI is zero years. Why is this? Well...the annual loan payment is less than the sum of the utility savings+NC Greenpower incentives + Duke Energy RECs. As the loan life shortens to say, 5 years, then the ROI creeps up to 10 years.
So essentially what this is says...is if you can refinance your home or purchase your home with some extra cash for the upgrade and put on a solar system, then you'll be golden with zero to one year ROI. The best loan terms I could find were 15 years loans on Home Equity. Other than that most loans are limited to 5 years.
Of course, as my wife says....this is all dependent on if you can even put this on your roof. Who knows what our homeowners association would say about the panels. Lots of folks out there can be ignorant...
Thursday, December 15, 2011
Enertia Homes and Reblog
OK...so I saw Enertia Homes the first time on the GreenHD network and thought it was uber cool. That was at least a year ago. Well, for some raeson, I just remembered about it and started looking at it. It's a pretty awesome concept. Here's the link to the MFR website: http://enertia.com/
They are located in NC and they produce very low energy (maybe net-zero in certain locatiosn) homes paired with solar hot water and solar PV. The homes use a doube-envelope system to heat and cool the house in lieu of an HVAC system. Well..in NC, I'm sure we'll at least want a dehumidifier. Oh...and if you have a picky spouse...then maybe you'll want a small HVAC system. However, you could go ahead and install a small geothermal system to minimize those costs...maybe even help the hot water generation too.
On the website, they do have information on energy usage for a house in Durham, NC. They spent a total of $572 over the year for the home (~$48/month). That's not too shabby...
And heres a reblog from another fellow blogger about the homes.
http://sustainablog.blogspot.com/2007/07/enertia-home-modern-marvel-or-lot-of.html
As they've said...there's not a lot of data on these homes...and then there's apparently a fire risk too.
I may just look into beefing up the insulation in my walls using this retrofoam stuff. It can be installed into existing wall cavities that already have insulation in them. That's pretty cool...but it really depends on how much is costs to install and if there's any ROI. If you consider my average utility bill is probably around $70/month...then even reducing it by 50% would save me $420/year. If installing the retrofoam cost me $7,000 to install (probably not unrealistic...I had a quote to encapsulate my crawl space that was $7,000 which included the liner, dehumidier, spray foam, etc. A second quote with everything but the spray foam was $2800..so $4200 just for the spray foam in my crawl space) then the ROI is 16.7 years.
Given that, it would be more cost effective to go solar as I said in my previous posting. That would give me an ROI of 9 years...
They are located in NC and they produce very low energy (maybe net-zero in certain locatiosn) homes paired with solar hot water and solar PV. The homes use a doube-envelope system to heat and cool the house in lieu of an HVAC system. Well..in NC, I'm sure we'll at least want a dehumidifier. Oh...and if you have a picky spouse...then maybe you'll want a small HVAC system. However, you could go ahead and install a small geothermal system to minimize those costs...maybe even help the hot water generation too.
On the website, they do have information on energy usage for a house in Durham, NC. They spent a total of $572 over the year for the home (~$48/month). That's not too shabby...
And heres a reblog from another fellow blogger about the homes.
http://sustainablog.blogspot.com/2007/07/enertia-home-modern-marvel-or-lot-of.html
As they've said...there's not a lot of data on these homes...and then there's apparently a fire risk too.
I may just look into beefing up the insulation in my walls using this retrofoam stuff. It can be installed into existing wall cavities that already have insulation in them. That's pretty cool...but it really depends on how much is costs to install and if there's any ROI. If you consider my average utility bill is probably around $70/month...then even reducing it by 50% would save me $420/year. If installing the retrofoam cost me $7,000 to install (probably not unrealistic...I had a quote to encapsulate my crawl space that was $7,000 which included the liner, dehumidier, spray foam, etc. A second quote with everything but the spray foam was $2800..so $4200 just for the spray foam in my crawl space) then the ROI is 16.7 years.
Given that, it would be more cost effective to go solar as I said in my previous posting. That would give me an ROI of 9 years...
Thursday, December 8, 2011
December Energy Bill
Wow...I sure have been slacking on the ole' blog front. My bad...
Anyhow, I got in our latest energy bill for December (OK...really its for November, but the bill date is December). Here's the results:
Total kWH = 963 (2010 = 1374)
Days = 30
Avg kWh/d = 32.10/day (2010 = 45.8 kWh/d)
% Savings vs 2010 = 29.9%
% Savings compared to former 1300 sf townhome = 108.3%
OK...so the trend continues. We've consistently been around 30-40% savings versus 2010 while using about the same energy as our former (half-sized) townhome.
Winter promises to hold the largest savings. Look at the energy used last year:
Jan 2010 = 3,224 kWh (94.8 kWh/d)
Feb 2010 = 1967 kWh (70.2 kWh/d)
The largest energy usage day we've had was a couple days ago. It was in the high 30s, low 40s....we did 4 loads of laundry (re: dryer) ...and we cooked a lot. On that day we used 60 kWh. Our largest average month (July) has been 32.9 kWh/d. So keeping up with this pattern would mean that we're looking at the potential for savings in the range of 50-67%. Only time will tell how well we do.
Anyhow, I got in our latest energy bill for December (OK...really its for November, but the bill date is December). Here's the results:
Total kWH = 963 (2010 = 1374)
Days = 30
Avg kWh/d = 32.10/day (2010 = 45.8 kWh/d)
% Savings vs 2010 = 29.9%
% Savings compared to former 1300 sf townhome = 108.3%
OK...so the trend continues. We've consistently been around 30-40% savings versus 2010 while using about the same energy as our former (half-sized) townhome.
Winter promises to hold the largest savings. Look at the energy used last year:
Jan 2010 = 3,224 kWh (94.8 kWh/d)
Feb 2010 = 1967 kWh (70.2 kWh/d)
The largest energy usage day we've had was a couple days ago. It was in the high 30s, low 40s....we did 4 loads of laundry (re: dryer) ...and we cooked a lot. On that day we used 60 kWh. Our largest average month (July) has been 32.9 kWh/d. So keeping up with this pattern would mean that we're looking at the potential for savings in the range of 50-67%. Only time will tell how well we do.
Monday, November 7, 2011
November Energy Bill
I got the latest Energy bill in yesterday. Here's the results:
Nov 2011-
Total KWH: 734
Days: 29
Avg KWH/d: 25.30
2010 Avg Kwh/d: 26.28
Savings: 3.67%
Comparing to 2009 townhome: 108.1%
Yup...not a huge savings. But then recall, the bill is label November, but it's actually for October 4 - November 2nd. Well...for about half of October, the HVAC system was turned off. Then we started getting those cold nights (30s-40s) so the heat was turned on. Those cold temperatures are unusual for this time of the year (did you guys see the October New England snow storm?)
Overall, I think we're fine. Now NEXT month is going to be exciting. As a preview, last year we used 1374 kWh for the month or 45.80 kWh/d. We're averaging 32.2 kWh/d right now...and that will be back to the normal ~30% savings. After that in January we used 3,224 kWh and in February it was 1,967 kWh....I expect HUGE savings over those months. Since we've installed the Geothermal system, our largest month was 1086 kWh...
Nov 2011-
Total KWH: 734
Days: 29
Avg KWH/d: 25.30
2010 Avg Kwh/d: 26.28
Savings: 3.67%
Comparing to 2009 townhome: 108.1%
Yup...not a huge savings. But then recall, the bill is label November, but it's actually for October 4 - November 2nd. Well...for about half of October, the HVAC system was turned off. Then we started getting those cold nights (30s-40s) so the heat was turned on. Those cold temperatures are unusual for this time of the year (did you guys see the October New England snow storm?)
Overall, I think we're fine. Now NEXT month is going to be exciting. As a preview, last year we used 1374 kWh for the month or 45.80 kWh/d. We're averaging 32.2 kWh/d right now...and that will be back to the normal ~30% savings. After that in January we used 3,224 kWh and in February it was 1,967 kWh....I expect HUGE savings over those months. Since we've installed the Geothermal system, our largest month was 1086 kWh...
Thursday, November 3, 2011
Cost of Going Solar...is it worth it?
Ok...so I've been mulling over additional ways to save money. If you've been following...that's included changing out the HW heater for one. I've also been thinking about replacing the siding on my house (which is the old Masonite stuff...which had a lawsuit against it...which expired right after I bought my home)...whch would include Housewrap which should reduce energy bills by 10-15%.
The other thing, I've been thinking about is solar power. Adding this in would significantly reduce my bills...but at a significant cost. So I did some research and came upon a handy website that allowed me to determine the cost of solar. This saves me a lot of heartache of doing it myself...and it appears to be fairly comprehensive. The site is: solar-estimate.org and its a free site that is run by "Energy Matters LLC" which makes web-based tools for marketing and sales in solar, wind, renewable energy, and energy efficiency industries. So given that this site was probably paid for by a professional organization looking to advance the industry and not one specific business, I feel fairly comfortable using the tool.
So, I input my location, selected my Utility, along with some other minor stuff (residence, I want to review solar PV, etc) and it says I have a solar rating of "GREAT" at 5.09 kWh/m^2/day. I've seen this value before and when I look at those "solar maps", my area is right around 5, so this makes sense to me. This is the "average solar radiation during an average year". Next I entered the following information:
The other thing, I've been thinking about is solar power. Adding this in would significantly reduce my bills...but at a significant cost. So I did some research and came upon a handy website that allowed me to determine the cost of solar. This saves me a lot of heartache of doing it myself...and it appears to be fairly comprehensive. The site is: solar-estimate.org and its a free site that is run by "Energy Matters LLC" which makes web-based tools for marketing and sales in solar, wind, renewable energy, and energy efficiency industries. So given that this site was probably paid for by a professional organization looking to advance the industry and not one specific business, I feel fairly comfortable using the tool.
So, I input my location, selected my Utility, along with some other minor stuff (residence, I want to review solar PV, etc) and it says I have a solar rating of "GREAT" at 5.09 kWh/m^2/day. I've seen this value before and when I look at those "solar maps", my area is right around 5, so this makes sense to me. This is the "average solar radiation during an average year". Next I entered the following information:
From above, nearly all of this stuff was pre-filled in for me. Note that I said I only wanted to put in a 25% system (2kW)...since if I did do this, I'd want to start off small. The install cost shown is from a help file that shows its about $9/WDC <2 kW installed and $8/WDC for systems =>2kW. Note that my utility inflation rate was suggested at 3.78% based on whatever data, solar-estimate.org has. This actually is probably pretty close. I've looked this value up numeous times for Engineering reports and, in general, Utility inflation is about 4%. So I'm comfortable with this.
So after, I put this stuff, in I got the following for system sizing:
The energy bill is right on. When I track my energy bills via Mint.com, I get roughly the same. OK...so this says I'd need roughly a 2.25 kW system and I'd need 226 ft2 of roof area. Note:. 2.25kW is roughly how much energy my geothermal system needs when its running (for half...so either the upstairs or the downstairs). .How big is 226 ft2? If I assume a 4-ft long solar panel and I put 2 end-to end, then I'd need an area that's 8-ft x 28-ft. That's really not all that big. This estimates an annual production of just under 3000 kWh. Note that there is some hidden math behind here...because this is not just simply: 226 ft2 --> 21m2 x 5.09 kWh/m2/day * 365 days/yr...because this equals 39,000 kWh/yr. The 226ft2 (or 21m2) is based on 10W/ft2 average solar panel sizing. So this obviously has some fairly high conservatism in it. I get fairly similar values when I run the Dept of Energy's PV Watts...this gives me a solar rating of 5.07 kWh/m2/day and an energy production of 2976 kWh/yr. If I use data from an existing PV system (adjacent to the fire station roughly 2.5 miles away, I get 4.91 kWh/m2/day and and equivalent annual production of 2863 kWh. So this is neighborhood.
Next it gave the rough cost for the system:
$18.1K? Installed cost? OK...I can believe that. I've heard numbers floating around and this makes sense to me. The next part is really cool...they show me how the incentives work. I've seen these before since I got the same one's for my geothermal system...for exception of the Duke Energy and NC Greenpower adders:
Overall...this is showing my a rough ROI of 9 years. That's not overly great...but then again, it's not overly bad either. Most of my other options (i.e. HW Heater) don't have an ROI for 10+ years. The information below gets into more detail on the savings.
Overall...this appears to be a good investment if you take into account the 25-yr net present worth. So maybe someday, I'll have some extra cash on hand and I'll look into this. Also...possibly by then...prices of solar panels will have come down helping the ROI. I definitely like the idea.
One thing I'm still tentative about is what maintenance needs to occur. Do I need to go up to my roof every fall and get the leaves off? Do I need to wash the system (espeically if a bird decides to unload)? Anything else I need to do?
When and if I install a system....I'm sure I'll blog about it...so you'll know.
Any thoughts out there?
Wednesday, November 2, 2011
Brrrrr...
Hello all-
It's gotten cold in the Carolina's the past couple weeks. Morning temperatures have been flirting with the high 30s...with afternoon temperatures in the high 50s, low 60s. You know what that means....the heat is on. Below is the TED historical usage. Electricity usage is up into the 30 kWH/d range. Those days that show usage in the 40 KWH/d are when we're doing laundry (Sunday/Monday). It's amazing how much the eletric dryer uses even though we have a high efficiency washer which really spins the water out of the clothes. Maybe I'll investigate the default settings on the dryer to see if I can save some energy there...but I kind of doubt I'll find anything.
My HW usage is up too...not suprising as anyone can tell you how nice a hot shower is on a cold AM....even though I have the super-low flow 1.5 gpm showerhead. And now I have the results to show it (see below). On average we're using about $0.50-$0.60 per day on HW. One an avearage month...that's $15 in my Bill. Probably at best, I can reduce that by about 50% if I upgrade my HW heater to one of those GE Geospring Units and run it in series with my existing HW (turned off) to maximize the geothermal desuperheater. At that amount ($7.50/mo), I'd save $90/year. Thus it would take roughly 10 years to pay off the HW heater. That's not exactly a great ROI, but who knows...maybe prices will drop to make it more attractive. I really wish Duke Energy would offer a rebate on higher efficiency hot water heaters to make it worthwhile. A $300 rebate would mean 3 years off the ROI, which is great. But...Duke energy's program is for HVAC only...bah!
FYI...so the NC Utilities commission, denied Duke Energy's request for the 15.4% rate increase this year. Instead they recommended a ~5% increase. Duke's pretty pissed about this and I'm sure they'll find another way to get the rates out of us. Maybe I'll need to start really looking at solar panels soon...
It's gotten cold in the Carolina's the past couple weeks. Morning temperatures have been flirting with the high 30s...with afternoon temperatures in the high 50s, low 60s. You know what that means....the heat is on. Below is the TED historical usage. Electricity usage is up into the 30 kWH/d range. Those days that show usage in the 40 KWH/d are when we're doing laundry (Sunday/Monday). It's amazing how much the eletric dryer uses even though we have a high efficiency washer which really spins the water out of the clothes. Maybe I'll investigate the default settings on the dryer to see if I can save some energy there...but I kind of doubt I'll find anything.
 |
| TED Historical Usage up to 11/2/2011 |
My HW usage is up too...not suprising as anyone can tell you how nice a hot shower is on a cold AM....even though I have the super-low flow 1.5 gpm showerhead. And now I have the results to show it (see below). On average we're using about $0.50-$0.60 per day on HW. One an avearage month...that's $15 in my Bill. Probably at best, I can reduce that by about 50% if I upgrade my HW heater to one of those GE Geospring Units and run it in series with my existing HW (turned off) to maximize the geothermal desuperheater. At that amount ($7.50/mo), I'd save $90/year. Thus it would take roughly 10 years to pay off the HW heater. That's not exactly a great ROI, but who knows...maybe prices will drop to make it more attractive. I really wish Duke Energy would offer a rebate on higher efficiency hot water heaters to make it worthwhile. A $300 rebate would mean 3 years off the ROI, which is great. But...Duke energy's program is for HVAC only...bah!
 |
| TED HW Usage - Oct 31, 2011 |
Sunday, October 9, 2011
October Bill
Howdy folks-
The good news just keeps coming. This month's bill came in at 771 kW over 32 days or 24.1 kWh/d. That's ~35% under last year's bill of 37 kWh/d. That's to be expected since we've averaged 35% under for the past 5 months. Compared to our former townhome, we're 4% over. Can't complain...overall itsFantastic!
I expected the next couple months to not be as great because we're moving into Fall and the HVAC system will most likely not turn on at all. There have been some cold nights recently with my wife turning on the heat a couple of mornings (Brrr).
I've graphed my energy usage since 2009 below. Some things to note:
Jan 2009 - March 2010 we were still in our 2005, 1300 sf townhome.
Then in April 2010, we moved into our current home (1984, 2700sf).
Finally, in April 2011, we installed the geothermal heat pump.
The energy savings is fairly obvious (green bars starting in April, month 4). What's pretty cool is that you can see how efficient our home is compared to our previous townhome which was newer (2005) and less than half the size (red bars). Neat-o, huh?
Now I need to anticipate what Winter's going to bring. Supposedly, the geothermal system is significantly more efficient in heating mode than cooling mode. It's said that its somewhere around 67-80% more efficient. Only time will tell...
The good news just keeps coming. This month's bill came in at 771 kW over 32 days or 24.1 kWh/d. That's ~35% under last year's bill of 37 kWh/d. That's to be expected since we've averaged 35% under for the past 5 months. Compared to our former townhome, we're 4% over. Can't complain...overall itsFantastic!
I expected the next couple months to not be as great because we're moving into Fall and the HVAC system will most likely not turn on at all. There have been some cold nights recently with my wife turning on the heat a couple of mornings (Brrr).
I've graphed my energy usage since 2009 below. Some things to note:
Jan 2009 - March 2010 we were still in our 2005, 1300 sf townhome.
Then in April 2010, we moved into our current home (1984, 2700sf).
Finally, in April 2011, we installed the geothermal heat pump.
The energy savings is fairly obvious (green bars starting in April, month 4). What's pretty cool is that you can see how efficient our home is compared to our previous townhome which was newer (2005) and less than half the size (red bars). Neat-o, huh?
Now I need to anticipate what Winter's going to bring. Supposedly, the geothermal system is significantly more efficient in heating mode than cooling mode. It's said that its somewhere around 67-80% more efficient. Only time will tell...
Sunday, September 25, 2011
Flash-back...sealing my home
Ok...so I know I've promised this for a while and I've finally gotten my ducks in a row. So...be prepared to go back in time and see some of my initial work sealing my home....scooby-doo style. Key the wavy lines:
<<>>><<<>>><<<>>><<<>><<>>><<<>><<>>><<>>><<>><<>><<>>><<<>>><<>>><<>>>
So when I got my initial energy audit (a birthday present from my wife...she's awesome), there were a handful of key things that I needed to do. Kudos to ProEnergy and Eric Wall for performing the audit. And again to my beautiful wife for getting me an awesome present. OK...below I'll discuss two fixes:
First up...I had no door sweeps. Seriously...none of my doors. When I got down onto the floor, I could look outside. On one door...my backdoor...the opening had to be at least 1/4". The fix was simple...install door sweeps. Of course, only one of my doors as a standard sized...so when I bought the door sweeps from Lowe's, I had to do some sawing. It was no big deal...but it wasn't totally painless. For the majority of my doors I bought the door sweep that attached to the outside of the door so when the rubber wears out I can get at it easily. Not surprising...it makes a big difference...and there's no highway for bugs to enter the house either.
The second big thing we needed to fix was found using the thermal gun. And I kind of knew something was up in my bonus room (i.e. finished room above the garage) when it was significantly warmer (10F) than the rest of the house. Well...apparently there was insulation missing in the ceiling of the bonus room. And truthfully...the pictures looked as if a little kid grab random pieces and ripped them out. On top of that, while there was insulation in the attic storage areas on either side of the room...that didn't stop the air movement. So to fix this, I had an insulation company come in and replace the insulation. They included a vent to maintain air movement when is good. Then the fun stuff began. Below is a pic of the bonus room attic space before:
The pic below is a picture of the work in progress with my wife. What we did was install rigid styrofoam insulation on the outer joists and then seal the joints with HVAC tape. What this did was provide another layer of insulation (this stuff is R5) as well as stop the air movement.
Once we did this to the walls, I added insulation to the doors (there was none), put on weather stripped to the doors (there was nothing there either), and we installed radiant barrier on the opposite joists. Oh yeah...I also had to do some caulking on the molding around the door to stop air leaks there as well. All of this had a profound effect. Oh...and I found my ventilation fan in the attic above the bonus room was broken too...I had to replace the motor on the fan. And while I was at it I changed out the thermostat too. OK...so the temperature in that room now is only about 2 degrees different from the rest of the house. And when I had the energy audit guys back, they could easily see the difference on the thermal camera.
This fix was fairly easy and took about a day to do...and I know it's paying dividends. That's because when I walk the dog I see my neighbors with a window air conditioner sticking out of the window of their bonus room. And talking with HVAC guys, they typically up-size systems or install dedicated units just for bonus rooms. Yet...maybe all you need to do is some minor modifications and it'll do just fine.
So for any folks out there who have a similar issue...try this stuff first. It worked for me...
Friday, September 23, 2011
LED Light Bulbs
Ok...as I'm sure most of you may expect, nearly all my light bulbs in my home are energy efficient. Nearly all are CFLs throughout the house....nearly all are 13W with only a couple being 23W (outdoor lights). There's only 5 lights that are not:
1) Master Bedroom ceiling fan. I have 1 @ 40W bulb here. For some reason the CFLs flicker...and I've tried all the 'fixes' online and none work. So I'm stuck with the 40W bulbs. At least I'm only using 1 bulb instead of 2.
2) Dining Room chandelier. It's dimmable and has 5 @ 40W bulbs.
3) Breakfast Nook chandelier. Same as #2, but has 6 @ 40W bulbs
4) Kitchen track lighting. It's dimmable and has 5 @ 50W GU10 bulbs
5) Entry way chandelier. 3 @ 40W bulbs.
Out of all these lights, the Kitchen and breakfast nook lights are what I use by far the most. As I'm typing this I'm glancing at my TED5000 seeing the two lights...dimmed...still using about 350W. Ugh!
So changing these two lights out...11 bulbs...could provide some good savings. However, I just can't stomach paying the high prices for light bulbs. A non-dimmable Chandelier CFL light bulb is $4 each. That's at least fairly reasonable...I could probably switch out the Entry Way chandelier with these. But not my two dimmable chandeliers. A 5W (25W equivalent) dimmable CFL light bulb is $8 each. It's $15 for a LED version (4W) nondimmable bulb. To get dimmable...$23. So, if I wanted to go LED, it would cost me $138 to replace the one dimmable chandeliers. Seriously?!? To replace my kitchen lighting with dimmable LED GU10 bulbs is $32 EACH. That's another $160. Total = $298....before shipping and taxes. Adding in the other dimmable chandelier would add in another $115 for $413 total.
I just don't think I can stomach this. I know there's the math that says they pay for themselves....but I just need to check for myself.
So let's take the kitchen light...5 @ 50W light bulbs = 250W when on @ full power (side note: with the dimmer I'm rarely at full power). Talking with my wife...let's assume it's on 3 hrs/day on average. That's 750Wh/d or $0.075/day at $0.10/kWh. On average that's $2.28/month or $27.38/year. A new LED light bulb appears to be 6.5W for a 50W 'equivalent'. That equates to 97.5Wh/d or $0.00975/day or $3.56/yr. So annual savings on this light would be $23.82. Thus, my return on investment would be: $160/23.82 = 6.72 years. That's a pretty dang long time for a light bulb. Now the dimmable LED light bulb claims that it'll last 25,000 hours (http://www.polar-ray.com/GU10-LED-Bulbs_c_159.html). I've seen this before...my CFL's "claim" they'll last 12,000 hours....and I have yet to be convinced (I've replaced burned out CFLs). OK...so 25,000 hours is equivalent to 2.85 years if run 24/7. Converting to 3 hrs/day that's 22.83 years. So, even cutting this in half to ~11.4 years still shows the bulbs will pay for themselves.
Still...I think I'm going to wait until prices are more reasonable. It's said that prices are falling rapidly...so maybe once my ROI is closer to 2-3 years will I decide to 'splurge'. Until then...I think I'll just deal with my $2.28/mo....and truthfully it's going to be less than that because I use my dimmer...a lot. I'm constantly turning the lighting down (with my wife doubling-back to turn it back up...and then I'm back...etc, etc). It sure would be nice to not have to worry constantly about those lights...
1) Master Bedroom ceiling fan. I have 1 @ 40W bulb here. For some reason the CFLs flicker...and I've tried all the 'fixes' online and none work. So I'm stuck with the 40W bulbs. At least I'm only using 1 bulb instead of 2.
2) Dining Room chandelier. It's dimmable and has 5 @ 40W bulbs.
3) Breakfast Nook chandelier. Same as #2, but has 6 @ 40W bulbs
4) Kitchen track lighting. It's dimmable and has 5 @ 50W GU10 bulbs
5) Entry way chandelier. 3 @ 40W bulbs.
Out of all these lights, the Kitchen and breakfast nook lights are what I use by far the most. As I'm typing this I'm glancing at my TED5000 seeing the two lights...dimmed...still using about 350W. Ugh!
So changing these two lights out...11 bulbs...could provide some good savings. However, I just can't stomach paying the high prices for light bulbs. A non-dimmable Chandelier CFL light bulb is $4 each. That's at least fairly reasonable...I could probably switch out the Entry Way chandelier with these. But not my two dimmable chandeliers. A 5W (25W equivalent) dimmable CFL light bulb is $8 each. It's $15 for a LED version (4W) nondimmable bulb. To get dimmable...$23. So, if I wanted to go LED, it would cost me $138 to replace the one dimmable chandeliers. Seriously?!? To replace my kitchen lighting with dimmable LED GU10 bulbs is $32 EACH. That's another $160. Total = $298....before shipping and taxes. Adding in the other dimmable chandelier would add in another $115 for $413 total.
I just don't think I can stomach this. I know there's the math that says they pay for themselves....but I just need to check for myself.
So let's take the kitchen light...5 @ 50W light bulbs = 250W when on @ full power (side note: with the dimmer I'm rarely at full power). Talking with my wife...let's assume it's on 3 hrs/day on average. That's 750Wh/d or $0.075/day at $0.10/kWh. On average that's $2.28/month or $27.38/year. A new LED light bulb appears to be 6.5W for a 50W 'equivalent'. That equates to 97.5Wh/d or $0.00975/day or $3.56/yr. So annual savings on this light would be $23.82. Thus, my return on investment would be: $160/23.82 = 6.72 years. That's a pretty dang long time for a light bulb. Now the dimmable LED light bulb claims that it'll last 25,000 hours (http://www.polar-ray.com/GU10-LED-Bulbs_c_159.html). I've seen this before...my CFL's "claim" they'll last 12,000 hours....and I have yet to be convinced (I've replaced burned out CFLs). OK...so 25,000 hours is equivalent to 2.85 years if run 24/7. Converting to 3 hrs/day that's 22.83 years. So, even cutting this in half to ~11.4 years still shows the bulbs will pay for themselves.
Still...I think I'm going to wait until prices are more reasonable. It's said that prices are falling rapidly...so maybe once my ROI is closer to 2-3 years will I decide to 'splurge'. Until then...I think I'll just deal with my $2.28/mo....and truthfully it's going to be less than that because I use my dimmer...a lot. I'm constantly turning the lighting down (with my wife doubling-back to turn it back up...and then I'm back...etc, etc). It sure would be nice to not have to worry constantly about those lights...
Tuesday, September 20, 2011
Hot Water Heater
So I've been trying to figure out what else I need to do to reduce my energy usage. There's things like:
1) Install high efficiency hot water heater
2) Replace siding on the house and put on house wrap
3) Install solar panels
4) Replace fridge
5) etc.
Well...I don't have a ton of money to spend so #2 and #3 are automatically out as those cost multiple thousands of dollars...if not above $10k. That leaves me with the fridge and HW heater. Well...at most the fridge might cost me $60-70/yr. And while I could get a bigger fridge that is more energy efficient...I'd still only save maybe $5-$10/yr. Yeah...that's not worth it. So that really leaves me with looking at the HW heater. I checked out TED from the last 48 hrs and it looks like the HW heater runs roughly 7x/day for about 10 minutes. The Geothermal system is not operating...it's that nice fall weather so I'm not heating or cooling. That also means the desuperheater is not generating hot water. At 4.8kW, that means the HW heater is using 5.6kWh/day. And I'm currently using 22 kWh/d. Thus, my HW is accounting for ~25% of my current total daily electricity usage. Obviously that value will change with increased HVAC usage...but its the numbers I have now.
OK...so one of those hybrid hot water heaters (http://www.geappliances.com/heat-pump-hot-water-heater/ claims a 62% reduction in energy usage compared to a standard hot water heater. I verified this by looking at that yellow tag energy information. My current 50-gal HW heater says it'll cost me $520/year and 4879 kWh/year. The hybrid says $198/yr and 1856 kWh/yr. There's lots of assumptions included in there (family of 4, using XX gallons per day, $0.105/kWh, yadda yadda)...but let's assume that this is relative and be scalable to my usage. I can't see why it wouldn't since it's based on usage.
This would mean I could expect my energy usage to reudce from 5.6kWh/day to 2.1 kWh/d. From a cost standpoint, that's $66/year in savings. My return on investment: $1000-$300 (tax rebate) = $700/$66 = 10.6 years. Not a great return, but it's a return...and its within a 'lifetime'. I should note that next year my electricity rates are going up 15%. And Dook Energy is trying to raise them another 15% the following year. Using just the one rate increases bring my savings up to $76/yr and make my ROI to 9.2 years.
One thing I should also note is that the hybrid HW heater is essentially an air source heat pump (ASHP) attached to a hot water heater. So when it runs...it's essentially an air conditioner. It's taking the heat from the air and transferring it to the hot water. That means my crawl space (where my HW heater is located) will become 'conditioned'. So no more dehumidifier needed (that's an extra 3 kWh/d minimum which isn't included here). So that's cool.
However, I'm a little worried if there's enough 'heat' down in the crawl space during the winter. I know last winter, the crawl space hung around 68F...and I had crappy vents in there. I know i probably had duct leakage...but it wasn't too signficant as I had the energy audit guys down there and I fixed the places that had bad leakage. I was reading online and some folks saw the unit drop temperatures down to 45-47F in their basements....which required them to drop a duct to give it some heat.
So I'm thinking what I'll do this winter is I'll insulated the door to he crawl space and then monitor the temperature in the crawl space to see what happens. If temperatures stay fairly warm, maybe I'll swap out the hot water heater...
Any thoughts out there?
UPDATE: Now there's always switching to gas to save moeny. But that's not cheap either. First, my hot water heater is in my crawl space. And I'd need to vent the exhaust....which I doubt I have space for. So for a standard gas hot water heater, I'd probably have to move it someplace else (garage?)...and I'd need an electrician and plumber for that. And that isn't cheap. I could go tankless and gas. Again I'd need to move things around...and that unit is ~$1500. And a 7.4 gpm unit ("2 uses") would still cost $223/mo @ 1.22/therm (using the Energy Guide). So its still not better than the hybrid uni...not to mention it'll be more expensive to purchase and install.
UPDATE 2: I just found this in the WaterFurnace Desuperheater User manual. Apparently, it's more efficient to install two HWs in series to allow the first one to be a preheat tank to maximize the desuperheater usage. I'll definitely have to think about this...
1) Install high efficiency hot water heater
2) Replace siding on the house and put on house wrap
3) Install solar panels
4) Replace fridge
5) etc.
Well...I don't have a ton of money to spend so #2 and #3 are automatically out as those cost multiple thousands of dollars...if not above $10k. That leaves me with the fridge and HW heater. Well...at most the fridge might cost me $60-70/yr. And while I could get a bigger fridge that is more energy efficient...I'd still only save maybe $5-$10/yr. Yeah...that's not worth it. So that really leaves me with looking at the HW heater. I checked out TED from the last 48 hrs and it looks like the HW heater runs roughly 7x/day for about 10 minutes. The Geothermal system is not operating...it's that nice fall weather so I'm not heating or cooling. That also means the desuperheater is not generating hot water. At 4.8kW, that means the HW heater is using 5.6kWh/day. And I'm currently using 22 kWh/d. Thus, my HW is accounting for ~25% of my current total daily electricity usage. Obviously that value will change with increased HVAC usage...but its the numbers I have now.
OK...so one of those hybrid hot water heaters (http://www.geappliances.com/heat-pump-hot-water-heater/ claims a 62% reduction in energy usage compared to a standard hot water heater. I verified this by looking at that yellow tag energy information. My current 50-gal HW heater says it'll cost me $520/year and 4879 kWh/year. The hybrid says $198/yr and 1856 kWh/yr. There's lots of assumptions included in there (family of 4, using XX gallons per day, $0.105/kWh, yadda yadda)...but let's assume that this is relative and be scalable to my usage. I can't see why it wouldn't since it's based on usage.
This would mean I could expect my energy usage to reudce from 5.6kWh/day to 2.1 kWh/d. From a cost standpoint, that's $66/year in savings. My return on investment: $1000-$300 (tax rebate) = $700/$66 = 10.6 years. Not a great return, but it's a return...and its within a 'lifetime'. I should note that next year my electricity rates are going up 15%. And Dook Energy is trying to raise them another 15% the following year. Using just the one rate increases bring my savings up to $76/yr and make my ROI to 9.2 years.
One thing I should also note is that the hybrid HW heater is essentially an air source heat pump (ASHP) attached to a hot water heater. So when it runs...it's essentially an air conditioner. It's taking the heat from the air and transferring it to the hot water. That means my crawl space (where my HW heater is located) will become 'conditioned'. So no more dehumidifier needed (that's an extra 3 kWh/d minimum which isn't included here). So that's cool.
However, I'm a little worried if there's enough 'heat' down in the crawl space during the winter. I know last winter, the crawl space hung around 68F...and I had crappy vents in there. I know i probably had duct leakage...but it wasn't too signficant as I had the energy audit guys down there and I fixed the places that had bad leakage. I was reading online and some folks saw the unit drop temperatures down to 45-47F in their basements....which required them to drop a duct to give it some heat.
So I'm thinking what I'll do this winter is I'll insulated the door to he crawl space and then monitor the temperature in the crawl space to see what happens. If temperatures stay fairly warm, maybe I'll swap out the hot water heater...
Any thoughts out there?
UPDATE: Now there's always switching to gas to save moeny. But that's not cheap either. First, my hot water heater is in my crawl space. And I'd need to vent the exhaust....which I doubt I have space for. So for a standard gas hot water heater, I'd probably have to move it someplace else (garage?)...and I'd need an electrician and plumber for that. And that isn't cheap. I could go tankless and gas. Again I'd need to move things around...and that unit is ~$1500. And a 7.4 gpm unit ("2 uses") would still cost $223/mo @ 1.22/therm (using the Energy Guide). So its still not better than the hybrid uni...not to mention it'll be more expensive to purchase and install.
UPDATE 2: I just found this in the WaterFurnace Desuperheater User manual. Apparently, it's more efficient to install two HWs in series to allow the first one to be a preheat tank to maximize the desuperheater usage. I'll definitely have to think about this...
Friday, September 16, 2011
TED is back
Woohooo! It ended up being a broken daugherboard. But it's all fixed and my display is back. Now back to being informed and nit-picky about where my electricity is being used...
Friday, September 9, 2011
September Duke Energy Bill
Yes folks, yet another month has passed and I was waiting at the mailbox eager with anticipation...for a bill. This month's electric bill came in and showed continued fantastic results:
Electricity Usage: 941 kWh
Days: 31
Avg Usage: 30.3 kWh/day
Comparing versus 2010: 37% savings (aka reduction in energy usage)
Comparing versus townhome of less than half this houses area (2009): 6% higher.
I'm thrilled. It appears that we've had a consistent ~40% reduciton in energy usage. And, I'm using about the same amount of total energy as if I were still in my former townhome. Just sweet!
I would expect the savinsg to be more if I can figure out where the humidity is coming from in my crawl space. I have the dehumidifier running 6 hrs on/6 hrs off. During that time, the humidity drops to 45% when on...then raises to about 55-60% when off. I'm not sure but it might be hitting the 45% humidity mark and turning off. I need to check the manual to figure this out. UPDATE: Yes, I verified this and once it hits around 45% (the setting on the unit is 50%), it turns off....and then restarts again when the humidity increases.
UPDATE on TED: Energy Inc (the MFRs of the TED unit) sent me a new display. Well, that one didn't work...it wouldn't connect to my gateway. After discussions with tech support, apparently they sent me the wrong model (there is a series 21 and a series 20...I have a series 20). That should arrive today. It'll be nice to have the ole' TED display around again...
UPDATE 2: FYI, my TED unit had 993 kWh for the month vs the 941 for Duke Energy. That's a ~5% error difference. I think the # of days was the same...but I think TED is setup to record from the 2nd to the 2nd, while Duke Energy this month went from the 6th to the 6th.
UPDATE 3: Well, the TED display arrived and this time it showed it was picking up a wireless signal, but again, it was not showing the data. Hrmmph! We'll see Tech support says this time. I have a feeling it's a firmware issue.
UPDATE 4: FYI...I have no idea why my August post is in front of my September post. Maybe once I update this post it'll move it ahead...maybe...I hope...
UPDATE 5: I finally fixed that August post...someone is double-posted...so I just deleted it. So very odd...
Electricity Usage: 941 kWh
Days: 31
Avg Usage: 30.3 kWh/day
Comparing versus 2010: 37% savings (aka reduction in energy usage)
Comparing versus townhome of less than half this houses area (2009): 6% higher.
I'm thrilled. It appears that we've had a consistent ~40% reduciton in energy usage. And, I'm using about the same amount of total energy as if I were still in my former townhome. Just sweet!
I would expect the savinsg to be more if I can figure out where the humidity is coming from in my crawl space. I have the dehumidifier running 6 hrs on/6 hrs off. During that time, the humidity drops to 45% when on...then raises to about 55-60% when off. I'm not sure but it might be hitting the 45% humidity mark and turning off. I need to check the manual to figure this out. UPDATE: Yes, I verified this and once it hits around 45% (the setting on the unit is 50%), it turns off....and then restarts again when the humidity increases.
UPDATE on TED: Energy Inc (the MFRs of the TED unit) sent me a new display. Well, that one didn't work...it wouldn't connect to my gateway. After discussions with tech support, apparently they sent me the wrong model (there is a series 21 and a series 20...I have a series 20). That should arrive today. It'll be nice to have the ole' TED display around again...
UPDATE 2: FYI, my TED unit had 993 kWh for the month vs the 941 for Duke Energy. That's a ~5% error difference. I think the # of days was the same...but I think TED is setup to record from the 2nd to the 2nd, while Duke Energy this month went from the 6th to the 6th.
UPDATE 3: Well, the TED display arrived and this time it showed it was picking up a wireless signal, but again, it was not showing the data. Hrmmph! We'll see Tech support says this time. I have a feeling it's a firmware issue.
UPDATE 4: FYI...I have no idea why my August post is in front of my September post. Maybe once I update this post it'll move it ahead...maybe...I hope...
UPDATE 5: I finally fixed that August post...someone is double-posted...so I just deleted it. So very odd...
Tuesday, August 30, 2011
Waiting on TED
Sorry for the delay. Still waiting on my TED display unit to show back up...and it's killing me. I'm still saving money...but I'm missing my display and its information. I can still see the data using my laptop or cell phone...but there's nothing like the 'glance' at the counter. I can say, that according to TED, I'm using less electricity than last month. It'll be another 3-5 days until I get my next Duke Energy bill and I'll know for sure.
Keep those fingers crossed.
UPDATE: I added a comment to my 'support ticket' and they just responded. The TED folks just responded to say that they are shipping out a replacement display today and I should have it on Tuesday. Sweet!
Keep those fingers crossed.
UPDATE: I added a comment to my 'support ticket' and they just responded. The TED folks just responded to say that they are shipping out a replacement display today and I should have it on Tuesday. Sweet!
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