LED light bulbs

OK, so I'm finally fully LED or CFL in the house.   Due to the energy efficiency lighting grant, I got myself some MR16 and candelabra bulbs among the other bulbs i ordered for the neighborhood.   So i gotta say...they look great!  I thought i might be disappointed...but no!

I posted some pics below.  The MR16 are Slyvania 5.5w bulbs (from Lowe's) which replaced 50w bulbs.  So that's 27.5w instead of 250w or a 89% reduction.  One issue is that these are non-dimmable apparently because they buzzed something awful until i replaced the dimmer switch.

Our kitchen light with the 5@5.5W LED bulbs, an 89% energy savings

Now the other lights are using the candelabra bulbs.  I put these into the chandeliers in our breakfast nook and dining room as well as our entry light.  Combined those used 620W through a combination of 11@40W and 3@60W bulbs.  They were replaced with Utilitech 3.5W bulbs (dimmable!) which now total 49W or 92% savings.  They were easy to install, even though removing those individual little light shades on the chandeliers was annoying.  Pics are provided below.

Our breakfast nook chandelier (ignore the mess, please)

The dining room chandelier.  Looks nice!

Optimize Geothermal with new Thermostat?

So I've mentioned this before in previous posts, but I'm not too happy with my Honeywell Prestige HD thermostat.  It's pretty looking, yes.  But for being a $300 thermostat, it's control options are not all that great. 



Honeywell Prestige HD Thermostat

One of things that I'm most unhappy about is the inability to control how the unit calls for Stage 1 and Stage 2.  Why is this important to me?  Well, Stage 1 is more efficient than Stage 2.  And it seems whenever I walk by the thermostat, the unit is registering that Stage 2 is running. 

Let's take a closer look....

In Cooling mode, Stage 1 has an EER (Energy Efficiency Rating) of 26.8 while Stage 2 is 18.6.  So Stage 1 is 44% MORE EFFICIENT than Stage 2. (FYI..in terms of SEER, Stage 1 should be about a 31 and Stage 2 is 21).  However, Stage 2 has a greater capacity:  27,200 BTUh vs 21,500 BTUh.  So Stage 1 would have to run 1 hour and 15.9 minutes to achieve the same heat transfer as Stage 2 in 1 hour.  However, even if you factor in the longer run time, Stage 1 is still 31% more efficient than Stage 2.  So it's definitely beneficial to run Stage 1.  This assumes that the desuperheater benefit is the negligible, which in reality probably factors Stage 1 (longer run times means closer to steady state operation and higher heat transfer efficiencies).   And longer run times and means less Start and Stops on the compressor which is beneficial to maintenance. 

Now let's look Heating.  This benefit is no where near as great.  Stage 1 has a COP (coefficient of Performance) of 4.7 while Stage 2 is 4.2.  This translates to a HSPF (Heating Seasonal Performance Factor) of 16.05 for Stage 1 and 14.34 for Stage 2, so Stage 1 is about 12% more efficient,  Stage 1 has a heat transfer rating of 16,200 BTUh while Stage 2 is 19,500 BTUh. So Stage 1 would have to run 12 minutes longer to achieve the same heating as Stage 2.  Inclduing the extra run time, Stage 1 is still 10.6% more efficient.  Now, if I assume the desuperheater is running scalping 5% of Stage 1 (it automatically turns off for Stage 2), then the savings plummets to 5.9%.  But it's still a savings, albiet small. 

So what does this mean in terms of dollars? I create the following table below using the 2011 Cooling Bills.  The savings do not include the last 7% increase in Duke Energy rates for this summer.

2011 Summer Cooling Bills:
	Energy	Days	kWh/d	Bill	Rev Bill	Savings
06/01/11	1086	33	32.91	103.14	71.58	31.56
07/01/11	888	28	31.71	86.97	60.36	26.61
08/01/11	941	31	30.35	90.65	62.91	27.74
09/01/11	771	32	24.09	79.75	55.35	18.30	(Red by 25%)
					total	104.21	per year
2011 Winter Heating Bills:
	Energy	Days	kWh/d	Bill	Rev Bill	Savings
11/01/11	963	30	32.10	92	86.54	5.46
12/01/11	1318	33	39.94	121	113.82	7.18
01/01/12	1075	29	37.07	103.18	97.06	6.12
02/01/12	1051	29	36.24	107.9	101.50	6.40
					total	25.17	per year
			Estimated Total Annual Savings	129.37	per year

So during the 2011 summer months, there's a chance for about $100 in savings.  During the winter...not a lot at only $25.  I could roughly double the winter savings if I disabled the desuperheater in the winter.  Overall...even at $125/year that's not bad at all.  A HUGE decrease...no...but still measureable.



Ecobee Smart Thermostat.  It also has web-enable features too.

 So how can I fix this?  Well, I was looking at the Ecobee Smart thermostat.  This thermostat would allow me to set Upstage timers such that the system will stay in Stage 1 as long as possible as long as it doesn't violate any rules (such as...the temperature continues to rise or drop by X degreesd during operation or the timer doesn't "time out' before reaching the goal temperature). 
If I go with the Smart thermostat, then it could cost me about $600 ($300/thermostat).  Being conservative, the ROI would be about 5 years.  If I were to go with the Smart's new cousin...the Smart Si (not nearly as cool as the Smart, slighly harder to install, etc)...then the ROI would be 3 years as the thermostats only cost about $200 each.  I could also do one of each too. 

And all of that is before I talk about the really cool (nerdy) features such as reports that track the inside temperature, your setpoint, and the systsem run time.  And it's web-enabled so I can control it from anywhere (my wife will not be happy about that)

What do y'all think?  The downside is that my thermostats are brand new...however that could be a blessing because I could probably sell them to offset the cost of the new one. 

Energy Audit Results! HERS Index = 71

Well, I finally got my energy efficiency results in....drum roll please....

I got a HERS index rating of 71. 

So, what does this mean?  Well, let's start with the basics...HERS (Home Energy Rating System) is the standard by which a home's energy efficiency is measured.  Here's a good explanation:  http://www.resnet.us/hers-index

From above my house is roughly 30% more efficeint that a standard newly built home in the US (HRES = 100).  As compared to "existing homes" (HERS = 130), I'm about 55% more efficient. 

Based on ASHRAE 90.2 (1993) Annual Energy Consumption Compliance, my home surpasses the minimum compliance by 22.1%.  For a house of my size, ASHRAE has an annual consumption score of 2,197 while my house has a score of 1,737.  My house also exceeds 2003 IECC compiance by 10.3% (IECC = 67.9 MMBTU vs 60.9 MMBTU).

The blower door test confirmed by infilration at 0.29 ACH (Natural).  This exceeds the ASHRAE 62.2 standard of 0.35 ACH. This also means that I need some mechanical ventilation because my house is becominng 'too tight'.  An Energy Recovery Ventilator (ERV) was recommended to maintain "healthy air".

What else was recommeded?  See below:

1) Radiant Barrier in the Attic to reduce radiant heat loads to the upstairs and to the upstairs HVAC system.  (I was planning on this, however, I need a ridge vent first so all the hot air can be directled out of the attic efficiently).
2) Tighten the ducts on the first floor (I already knew this and this should already be fixed when I HVAC taped the filter door shut.
3)  Install ERV (see previous comments).
4)  Seal all holes/cracks/ and seams @ the Garage to the House.  (I'm not sure what this means since we didn't find any cracks/seams with the garage).
5)  Block joists at rim band at bay windows (OK...I can probably do this with some polystyrene foam board)
6)  Block Floor Band at Bay Window with blue board and foam (Same as #5 as I can best figure)

7)  Conidtion Crawl space to improve HVAC performance.  (I was getting to this.  I just need to insulate the crawl space walls and I'll be ready to allow some conditioned air into the crawl space.
8)  Condition attic to improve HVAC performance.  (I have no intention of doing this.  At most I'm planning is the radiant barrier- #1).
9)  Replace windows to improve wall u-value.  Yeah...at most I'll probably just replace all my window shades to be the "light filtering" double wall cellulose shades.  These should increase the R-value of the window (with the shade closed) substantially.

What I found interesting was the annual energy profile:

 One note...due to RESNET standards (I believe), this is based on a worst case scenario (4 bedrooms + 1) Family of 5 living in my house.  So I'm not actually spenting ~$1750/yr on my home.  Last year is was only $1050.  And the "Family of 5" is what is pushing my Lighting and Appliances up so high.

This table is neat because it says what's contributing to heating/cooling. 

So ignoring lights/appliances for now since it's way overinflated...this essentially shows that heating is predominate followed by cooling and water heating.  To reduce heating costs, it appears I need to do the siding project which would reduce infiltration and add insulation to the above grade walls.  However...if you really think about it...that project doesn't save me such.  Let's say I can reduce the infiltration and wall costs by 50%...That only saves me $137 per YEAR.  The siding project will cost me at least $10k for an ROI of 73.3 years.  Yes, it will make my house look nicer, but it isn't the energy monster I was hoping for.

For cooling, I really don't have a big winner unless I can reduce the internal gains...uhh...how do I do that?  Stop the fridge?  No indoor cooking during the summer?  Sleep outside?

And then there's hot water.  If I install one of those air source heat pump hot water heaters (such as a GE Geospring) then I could probably reduce that number to about $90/year.  And if you count reducing the crawl space dehumidifer usage by 50%, then I get about $180 per YEAR savings.  Yes...again...not a lot..even with the further optimization of my geothermal desuperheater (using two tanks in series).

Going back to the lighting and appliances.  If I look at the months that I am not using any HVAC, I'm essentially using 610 kWh/mo (20 kWh/d) of electricity.  About 30% of this goes directly to the crawl space dehumidifier (6 kWh/day).   Then there's hot water which is currenly about 20% (4 kWh/day).  So 50% is going to two things. Best as I can tell...after that is the fridge (709 kWh/yr * 1/365 = 1.94 kWh/d), the HTPC (1.64 kWh/d), then the dryer (6 kW * 1.5hrs/week * 52 weeks/365 days = 1.28 kWh/day).  Then maybe we have cooking (who knows where this math pans out...maybe 1 kWh/d?) and then freezer at 0.7 Kwh/d. 

So if I really want to make a large dent in my energy usage, my next target really should be the Air Source Heat Pump Hot Water Heater which should save me roughly 2,000 kWh/year (5.5 kWh/d) if I assume a 60% reduction in hot water generation cost (using GE's value) and a 50% reduction in dehumidifer usage since the hot water heater is a glorified dehumidifer.   I'm more than liklely going to hold off on this project until November for the "Energy Star Tax Holiday" in NC where we get a tax free day for Energy Star appliances.  The total project cost will probably be about $1.2k.

May Energy Usage, Dehumidifer

Hello all, I'm back.

Below is my May 2012 Energy Usage numbers from Duke Energy:

Total KWH:  689  (TED measured = 696 kWh)
No. of Days:  33
May 2012 Average Daily Usage:  20.88 kWh/day
May 2011 Average Daily Usage:  17.53 kWh/day
Comparison:  -19.1%

I'm not surprised by these numbers.  It was a hot May and we were forced to use our A/C for at least a week.  In addition, in May 2011, I had not yet installed the crawl space dehumidifier.  That was installed on June 6, 2011 (exactly 1 year ago...look at that).  One thing I have found since then, is that the dehumidifer is an energy hog (and it's Energy Star rated!).  I plugged it into my Kill-a-watt meter and measured the usage for  a couple days.  I found out that the unit is using roughly 7 kWh/day.  Wowza!  That's 33% of my average daily usage during the 'fringe' seasons (when the HVAC is not in use).

So what do I do about it?  Well...I think the only thing I CAN do about it, is to go ahead with my house residing project.  When I do this, I plan to install housewrap (maybe even some polystyrene insulation).  The housewrap is supposed to help reduce air movement (and thus MOIST air movement) which should help significantly and reduce crawl space dehumidifer usage.

Why do I think that?  Well...here's my thoughts:  When I turned on the A/C (which dehumidifies) last month I did not notice any reduction in crawl space dehumidifer usage (and I was watching)...as my initial theory was that the rest of the house was responsible for the permeation of humidity in the crawl space.  To test this out,  moved the dehumidifer to the house and ran it.  Guess what?  The crawls space humidity increased to 65% (slowly) even though the rest of the house was at 55%.    So that wasn't it...so my next theory formed...the humidity is entering the crawl space from the wall cavaties.  This would make sense because the walls terminate at the crawl space.  Because I have painted walls (who knows how many layers), this creates a fairly impermeable membrane on the interior walls...so where does the humidity go?  Well...down to the crawl space where the dehumidifer is drawing air and creating a gradient.  Thus, by putting on the houswrap/insulation...I'll create an effective air barrier on the EXTERIOR walls...which should significantly reduce the amount of moist air entering the crawl space. And I'm certain air is entering the wall cavity beause most of my exterior lights have holes directly to the interior wall. 

That re-siding project is going to be pretty expensive ($8-10k), but at least it will help my house look nice while simutaneously increasing energy efficiency.  I highly doubt I'm going to emark on the project soon.  Maybe this fall at the earliest...

Energy Audit #2

OK...so I had another energy audit on Tuesday (it was free). This was one of those full-blown audits.  I got this as part of an energy grant I won for my neighborhood.

Essentially...if I did my math correctly...my house is fairly tight and is just above Energy Star 2.0 standards (ACH50 = 5.1; Energy Star 2.0 <5.0).  You certainly can't complain about this given that New Homes barely meet this standard with existing homes (like myself) are generally have ACH50's in the 10-20 range.  BTW...ACH50 is "Air Changes per Hour at 50 pascal".  That's the blower door test standard which simulates the pressure differential with a 20 mph wind.  I found this table online (I've yet to re-find it...if I do, I'll post the reference) which is a good description.

 

ACH50	Natural Air Change	Rating	% of Energy bill	% savings potential	Ventilation requirements
1.5	0.075	Super	2%	none	Requires constant energy recovery ventilation
3.5	0.18	Excellent	6%	1 to 3%	Will require occasional forced ventilation
5	0.25	Better	10%	2 to 4%	May require occasional forced ventilation
7	0.35	Good	14%	2 to 5%	Does not require additional ventilation
10	0.50	Fair	20%	3 to 10%	Start of excessive energy loss and over -ventilation
20	1.0	Bad	40%	5 to 20%	Excessive energy loss and over –ventilation.

The duct blaster showed my upstairs ductwork was better than energy star (3.69 CFM vs Energy Star <4 CFM) with the downstairs ductwork at 7.8 CFM****. 

**** We found after the test that the door to the filter at the downstairs airhandler was had some big gaps/leaks.  I have HVAC-taped over the gaps when I reinstalled the filter.  It's expected that these leaks were the cause of the unexpectedly high leakage...and now the downstairs ductwork should meet Energy Star standards. ****

 We'll see what the final results say...but I'm guessing it's going to say that my house is doing pretty well.

One thing I was hoping for, was that going through this exercise would identify my next project.  Well...it kind of didn't.

When we walked through the house with the IR camera (blower door maintaining -50 pa), we really didn't spot any significant air leaks.  That's good, right? There were some very small spots, but nothing to raise an eyebrow at.  And those small spots I can most likely fix with a small tube of caulking. 

So where does this leave me? 

Most likely I'm still doing the following projects:

1) Geothermal hot water heater.  This is adding in the second tank to optimize hot water generation
2) Insulate crawl space walls (R10) and make the crawl space part of the building envelope.  This should keep my downstairs wood floors warmer during the winter.
3)  Siding and housewrap.  I still want to replace my siding with Hardiplank really for looks.  But while I'm at it, I'm probably going to add in an air barrier.  Given my results...a simple housewrap will probably be sufficient (per my previous posts I was looking at adding in some rigid insulation).  From the Table above...I really don't have much % savings potential left.  So the simple housewrap should put me firmly in the ACH50 <5 catagory, if not approaching a ACH50 of 3.5. 

I should get the results of the audit next week...and of course, I'll fill y'all in on the details...

Happy Memorial Day1 

Repost: Tankless Hot Water Heaters

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/

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.

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!)

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!)

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...)

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.

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. 

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?

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...

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...

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.

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?

UPDATE: Geothermal Aux Heat and Desuperheater

Per my post yesterday I got to work on my HVAC system.  I completed the following:

• 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

I will say that while I was insulating the desuperheater piping, the geothermal system was on.  The temperature coming off the pipes was nice and toasty so insulating them should help a lot. 

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...

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.

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...

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...