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Tuesday, April 16, 2013

On track for another record low month

My TED 5000 Dashboard (4/16/2013)


Yes...I'm a little excited right now...but it looks like I'm on track for a new record low month. 

Wait a second, you say?  But the picture above shows you using more than the last record month (October 2012). 

Hold onto your hats, I say!  This month started out cold and I was still using heat until about April 6/7th!  It's now ~10 days later and my heat is turned off.  Check out the Day History below... 

Historical Data
 
From the pic above in the Daily History you can see 2 days where I was below 10 kWh/day.  That one day (4/12) was my lowest energy usage day ever..and I was at home which includes the AM showers before work.  Granted, I will concede, both days I ate out (Thursday after Ultimate, Friday after golf).  Tuesday (10.3 kWh/d) and Wednesday (10.4 kWh/d) incldues cooking.   Either way, take the last week (Mon 4/9--> Sun 4/14)..I've averaged 11.96 kWh/d.
 
Well..through today, I've used an average of ~15.3 kWh/day (221 kWh).  I need to lower that to <14.6 kWh/day to equal my October 2012 record.   I would need to average 14.44 kWh/day for the next 15 days to match that record.  If I go conservative on my last weeks usage and I average 13 kWh/day for the next 15 days, then I'll average 13.88 kWh/day which will be a new record. 
 
***GIGGIDTY***
 
Stay tuned for the official results.
 
BTW...you may have noticed the TED Monthly Historical my March 2013 usage of 25,219 kWh.  Obviously this is a mistake given last months blog posting.  This is a bug in the TED5000 software whenever there's a power outage.  I'm not sure why but it registered that I used ~4,000 kWh from 3/18 (19:00 hours) to 3/19 (0:00 hours). The folks at Energy Inc (maker of the TED5000) know this and are working on a way to mitigate this issue (TED recognizes and skips or users edit it out or whatever).  It's pretty annoying, yes...and I hope it gets resolved soon.
 
Another Update...my TED 5000 display charging base broke the other day. This is a case where I can actually blame the cat for something (yes, that was the cat farting....not me....).  Shew was rubbing against the unit (happy kitty?) and it just fzzled and stopped working.  The display works fine when I take it out of the charger as it goes to battery mode.  But when I put it into the base, the screen goes blank.  Although my unit was out of warranty, I'm lucky enough that the base is only $15 to replace.  I contacted Energy Inc and a new one is in the mail. 
 

Thursday, April 4, 2013

April Bill - Good and Not So Bad?

Howdy Readers-

Another month has passed (roughly) since my last post.  Time sure flies by doesn't it?  Well, it's been a COLD spring so far down in the Southeast US.  Only in the past week has it finally been above 60F consistently.  I say this as I glance outside where its supposed to be a high of 48F, gloomy, and rainy all day.  *UGH* 

Although the forecast does call for sun this weekend with temperatures in the high 60s.  Yippie!

So...let's see where we ended up this month, shall we?

April 2012
Total Energy Consumption:  704 kWh
Number of Days:  32
Average Daily Consumption:  22.0 kWh/day
Heating Degree Days:  117  (note:  only 14 days actual had HDDs)
Energy Consumption per HDD:  2.63 kWh/HDD (based on 14 days)

April 2013 (Mar 4 - Apr 2)
Total Energy Consumption:  737 kWh
Number of Days:  29
Average Daily Consumption:  25.41 kWh/day
Changed versus previous year:  -15.5%
Bill Savings vs 2012 Consumption:  -$0.52
Heating Degree Days:  444  (note:  28 days actual had HDDs)
Energy Consumption per HDD:  1.60 kWh/HDD 
kWh/HDD Savings vs 2012:  39.1%

OK...so at first glance, I did worse than last year.  I used about 16% MORE energy, but luckily it only cost me a whopping $0.52 more.  I think I can deal.  However, when you factor how cold it was this year as opposed to last year, then I'm doing just fine.  If I include the HDDs, I was roughly 39% MORE EFFICIENT than last year. 

 I will say that this was tricky to look at because I had to make an "executive decision" on how to quantify days that had zero HDDs.  For the month of April 2012, if I included all 32 days in my calculation, then it would have said I used ~6 kWh/HDD.  Yes, that's a valid number, but its highly skewed because for nearly most of the month had no heating was needed so it's only looking at my "base" consumption at the time.  So that doesn't give a good indication.  So instead I only used the number of days an actual HDD was recorded.  I did the same for my 2013 values.  This brought the values more in line for as shown below:

2011-2012
12/2011 = 2.16 kWh/HDD
01/2012 = 2.45 kWh/HDD
02/2012 = 1.90 kWh/HDD
03/2012 = 2.14 kWh/HDD
04/2012 = 2.63 kWh/HDD

2012-2013
12/2012 = 1.82 kWh/HDD
01/2013 = 1.75 kWh/HDD
02/2013 = 1.73 kWh/HDD
03/2013 = 1.45 kWh/HDD
04/2013 = 1.60 kWh/HDD

OK...so this makes sense to me.  I'm trending as expected.  So I'm going to consider this a "minor" victory. 

I really don't have any energy efficiency projects in the near future.  Closest that once could even consider may be new window shades in the upstairs.  As we prepare the nursery for the arrival of our twins, I would like to put in some nicer shades than the cheap versions (old school pull down things that I can never get it to stay when I pull it down).  I was thinking about window films.  I tossed in an example link.   I get a little security benefit from it (you can't just smash a window anymore as the window film holds the glass in place...at least for a little while) not to mention some privacy too.  An then there's the potential energy savings too.  We'll see...I contacted my local firm to see how much it would cost.  I'm just curious right now...but if the price is right, I may do it.    I'll let y'all know... 

 

Monday, March 18, 2013

March Bill, Results, and Year-end Review


Anybody else out there sick of winter yet?  I certainly am.  I just looked up and this time last March we were easily into the low 70s every day.  I will admit that the last 2 days were B-E-A-UTIFUL.  But alas today, it's back to being cold (44F) with a drizzle.  Ugh...

Anyhow, below is the information from my March Duke Energy Bill:

March 2012 (February - March)
Energy Consumption: 1,051 kWh
Number of Days: 29 days
Average Daily Energy Consumption:  36.24 kWh/day
# of Heating Degree Days (HDD):  491
Unit Energy per HDD:  2.14 kWh/HDD

March 2013 (February - March)
Energy Consumption: 901 kWh
Number of Days: 28 days
Average Daily Energy Consumption:  32.18 kWh/day (11.21% reduction vs 2012)
# of Heating Degree Days (HDD):  620
Unit Energy per HDD:  1.45 kWh/HDD  (32% reduction vs 2012)
Bill Savings vs 2012 ($0.1093/kWh average rate) = $23.18

Fantastic...another month of savings even though it was colder outside!

So now it's time for my year end review.  Why does this come in March?  Well...that's because that's when we move in.  Below is a nice table comparison


2010-2011 (April - March)
Energy Consumption = 15,750 kWh
Days = 349
Average Daily Consumption = 45.13 kWh/day
Adjusted Annual Consumption = 16,472 kWh/yr
(adjusted to 365 days)

2011-2012 (April - March)
Energy Consumption = 10,930 kWh
Days = 366
Average Daily Consumption = 29.86 kWh/day
Adjusted Annual Consumption = 10,900 kWh/yr
Energy Reduction versus 2010 = 33.8%

2012-2013 (April - March)
Energy Consumption = 9,018 kWh
Days = 367
Average Daily Consumption = 24.57 kWh/day
Adjusted Annual Consumption = 8,969 kWh/yr
Energy Reduction versus 2011 = 17.7% 
Energy Reduction versus 2010 = 45.6% 
Bill Savings (adjusted rate) vs 2011 = $311.01

Wow...just wow.  You're with me on this, right?  Since I've moved in, I've been able to reduce my energy consumption by nearly 46%!  And if you compare against 2011 (the Geothermal was already installed), then you can see we've reduced our consumption by another 18%.  

Can I do better?  Well...probably not much more.  I'm guessing its going to be slim pickins' after this unless I start generating energy via solar panels.  If anything I'm expecting to see reductions throughout the spring/summer until I hit October 2013.  That's when I installed the new water heater and saw some fantastic energy reductions which is probably contributing heavily to my current results.

Until then..I'll enjoy my numbers while I still can.

Tuesday, March 5, 2013

Updated (Non-Official) HERs Rating

Unofficial HERs Index for my House

So the other day I was bored and came across my former HERs rating report completed last May.  The report showed my house had a rating of 71 which meant that it was ~55% more efficient than a typical existing home (HERs rating =130) and ~29% more efficient than a standard new home (HERs rating = 100).   Since I've done a whole bunch of projects since then (most notably the attic radiant barrier and the GE Geospring), I was curious what my new score would be.

So looking through the report, in the footer it noted that the report was completed using the "REM/Rate - Residential Energy Analysis and Rating Software v12.99".  Using Google, I input the information and found the website for the software.  As I hoped, they provided a download for the software.  So I downloaded v14.1.  It's a 90-day trial version that's full featured except I can't print anything.  That's fine by me...I'm just playing anyway.

Luckily, my previous energy auditor, AltruEnergy, had sent me the REM/Rate file for my house (*.blg).  This was great because it meant I didn't have to re-enter all the information from the report!  Time saver!  After opening the file and doing the all-important "Save-As", I verified that my previous HERs rating did not change (it didn't) and then I started updated.   I added the following:
  • Added in R-5 to the foundation walls for the XPS I added this winter.
  • Added in R-5 to the Rim and Band Joist via the XPS I added this winter (1st floor only).
    • Note:  I have not added ventilation to the crawl space yet.  I’m waiting for my spring tune-up.  At that time, my HVAC guy is going to install the new vent in the crawl space.  So I didn’t update that in the file.
  • Added in Radiant Barrier to the ceiling (all except the small vaulted part in the bonus room) which I installed last fall.
  • Updated water heater to be my GE Geospring (EF=2.4) which includes an extra R-10 blanket I added myself.   It also runs in series to maximize desuperheater production.
  • Updated the geothermal system such that only 1 unit has a desuperheater (only the downstairs unit has one).
  • Added in my new fridge.  I got one of those French door fridges.  Not only is it bigger than my old one, but it uses nearly half as much energy per year.
  • I updated the dishwater information to reflect the actually kWh/yr via the Energy Guide.
  •  I updated the dryer to have moisture sensing which it has.
  • I updated the clothes washer with the actual information for my unit via the Energy Guide.
  • I updated my lighting to be 100% CFL.  It’s really more like 80% CFL and 20% LED.  But there's no option for LED in the software.  My exterior and garage fixtures are all CFL also so I put those to be 100% compliant.
  • I updated the ceiling fan CFM/watt to ~92 CFM/watt.  We have 5 ceiling fans in the house, all of which are energy star.  The old file said we only had 1.  I actually replaced the one in my master bedroom (which we use nearly every night in the summer) with one of those DC motor ceiling fans.  It uses 327 CFM/watt…which is about 3x better than other energy star ceiling fans!  It’s still on clearance at Home Depot online (Hampton Bay Winfield).
The results are below (it's also in the pic above if you were paying attention)...drum roll please....
Unofficial Home Energy Rating (HER) Certificate  Note:  The NO PRINT is because I'm using the trial version.
My unofficial revised HERs rating is a 54.  Sweetness!  So I'm nearly 50% more efficient that a new standard home.  And by energy star standards, my house is house is ~30% more efficient than a new standard home...assuming an energy star home is 30% more efficient than a standard home which would give it a HERs rating of 70.  In case you're wondering from the certificate above, I don't actually use $1,379/yr for energy.  I'm much below that ($1,091).  The above number is scaled for a family of 5.  There's only 2 of us now, although soon we'll be close with twins on the way.

Side note:  I'm not advocating that anybody else do this...I'm just an Engi-nerd that enjoys tinkering.  I did send my file back to my Auditor for a QA/QC check...so I will say these results are preliminary.  Although I'm not sure he'll say anything definitive just because he probably doesn't want to advocate for folks to use this software who don't know what they are doing.  Being a modeler myself, I understand that when it comes to models,  "junk in = junk out".  So if you don't know what you are doing, you could just producing useless numbers.

One of the nice things about having the software is that I can run some scenarios for projects that I was contemplating.  These include:
  • Replacing the siding and including R-5 XPS insulation (continuous barrier)
  • Replacing the windows with new Low-e, Argon filled windows
  • Install Solar Panels
Replacing the siding and the windows is an expensive proposition.  The siding itself would be ~$15k while the windows would probably be another $10k. Well, the software essentially told me not to bother.  Adding in the extra R-5 on the outside walls only saved be $50/yr!  The windows were another $50.  Obviously, doing it for energy saving purposes does not make sense.  Maybe for the windows installing a window film would make more sense because its significantly cheaper and would reduce the solar heat gain in the summer and the heat loss in the winter.  The return on investment would be significantly better while providing a similar benefit, although definitely not as great.  But it would be a fraction of the cost...if you believe the websites it's 10% of the cost.  So $1k vs $10k.  That could be palatable for my wallet.

The only thing that did make sense was the solar panels....but I pretty much already knew that.  The panels lowered my HERs rating to a 43.  However, that's a $4-5k investment.


Thursday, February 14, 2013

February 2013 Bill and Results

Howdy Folks-

Yes...I've been slacking.  I've been busy at work...blah blah blah, yeah I know...no excuses.  Well, I received my February Duke Energy Bill and the results are posted below:

February 2012 Bill
Total Energy Consumed:  1,075 kWh
Number of Days:  29
Average Daily Usage:  37.07 kWh/day
Heating Degree Days:  566
Temperature Normalized Average Usage:  1.90 kWh/HDD

February 2013 Bill (Jan 3- Feb 4)
Total Energy Consumed:  1,050 kWh
Number of Days:  32
Average Daily Usage:  32.81 kWh/day  (11.5% Reduction)
Heating Degree Days:  606
Temperature Normalized Average Usage:  1.73 kWh/HDD  (8.8% Reduction)
Rate Adjusted Bill Savings ($0.0996/kWh):  $14.71
One Year Rate Adjusted Bill Savings (April 2011- Feb 2013):  $296.18
Cumulative Rate Adjusted Bill Savings (April 2011- Feb 2013):  $680.45

Not too bad...a 11.5% reduction in usage compared to a year ago.  And when adjusting for temperatures differences, it's still nearly a 9% reduction.  I'll take that.  I also added in my one-year and the cumulative savings.  These savings do not take into account any system maintenance...although I doubt it would be much difference.

I will say that I do like using the Heating/Cooling Degree Day Data.  It certainly puts my HVAC-Energy usage into perspective.  I've been fairly consistent over the last 3 months (Recall the bills listed above actually represent the previous months usage):

11/2012 = 1.82 kWh/HDD
12/2012 = 1.75 kWh/HDD
1/2013  = 1.73 kWh/HDD

Interesting enough...Duke Energy Announced that they filed for a Rate Hike in NC.  They are trying for an 11.8% increase in residential Rates (among lower rate hikes for Commercial, Industrial, etc).  I expect that rates will eventually flatten out once either (a) Duke gets all its coal-fired plants in line with EPA air regs or (b) somehow Republicans destroy the EPA.  But of course, Duke Energy still recorded profits which were bolstered by the nice 7% rate hike they got last year.  Must be nice to be an energy company with low risk and can pass all costs onto its customers.

I will note that if this goes through as planned, then in in the past 3 years, rates would have increased by 22.2%.  When I evaluated my Geothermal system, I assumed a 24% (conservative 1.2%/yr) hike in electricty rates over 20 years.  Well...I guess my return on investment will be faster than I expected.  

Overall, maybe I should start looking at getting solar panels.  But, I have to build a screened in porch first...

Tuesday, January 8, 2013

January 2013 Bill Results...Another Big Reduction



A pic of my dog enjoying his new Xmas chew toy.  Yes, those are my super awesome slippers.  They certainly help keep the cold floors away from my toes!

Hello folks-

The holidays have past and so has another year of energy savings.  My Duke Energy Bill was not quite like a Christmas gift (Hey Duke...a great gift would have been NO BILL...hint hint) with the results posted below:

January 2012 Bill
Power Usage:  1,318 kWh
No. of Days:  33
Average Daily Consumption:  39.94 kWh/day
Bill:  $121

January 2013 Bill (Dec 3 - Jan 3rd)
Power Usage:  940 kWh
No. of Days:  31
Average Daily Consumption:  30.32 kWh/day  (24.1% reduction from 2012)
Bill:   $95.84
Absolute Bill Savings:  $25.16
Rate Adjusted Savings ($0.102/kWh): $50.47

I gotta say...wow.  I never expected this...especially since last year we were fully into the Geothermal.  My power usage was the same as last month at 30.3 kWh/day...I'm consistent.  It does make me wonder...let's check the Heating Degree Days (HDD's) from NOAA:

Dec 3 - Jan 3 2012
No. of HDDs:  533
No. of Days:  33
Average Energy Usage:  39.94 kWh/day
Average kWh/HDD:  2.45 kWh/HDD

Dec 3 - January 2013
No. of HDDs:  538
No. of Days:  31 
Average Energy Usage:  30.32 kWh/d
Average kWh/HDD:  1.75 kWh/HDD (28.8% reduction from 2012)

So, there was just as many HDDs as last year...and actually its more given that there's 2 less days.  Yet I had less Energy consumption, so I guess some of my energy reduction projects are paying off.  Most likely the GE Geospring ASHP water heater is really helping given that its this time of year (Brrrr...cold) that a lot of hot water is being used.  But I'm sure some of my other projects are helping out too:

1)  HTPC Upgrade
2)  New Fridge
3)  Better Controlling Ecobee Thermostats  (My HVAC installer is now an authorized Ecobee Installer...He liked my setup so much he signed up!)

Below are some pics from my Ecobee Home IQ for the month:

Downstairs Ecobee Information
Upstairs Ecobee Information

I will say that this Ecobee information is pretty useless to me as is.  I'm got lots of questions for Ecobee.  Such as the stars...how can 1 part of my house be 1 star and the other be 3 stars?  Especially if both systems appear to run identical hours!  And I have the same house information for each thermostat!  And yes, my system runs 68% more than a typical system in my area (BTW...what is my area?)...it's a heat pump...it will always run longer than most conventional systems.  Not to mention it was sized correctly so it will always run longer (closer to optimum) which is its maximum efficiency.  Not to mention, if you're comparing my geothermal heat pump to a furnace, my system will always run longer.  My system doesn't blast out 120F air for 5 min then turn off.   If you notice my average house temp set point is 65F.  That's pretty awesome!  I could let it go less, but there's no reason to.  That's because my house never cools lower than this temp.  Check out the pic below from my Ecobee:

Upstairs HVAC runtime information via my Ecobee Thermostat
First off...let me say that the information above is what really makes the Ecobee spectacular. OK...if you look at the graph above you'll see that when my house cools my system just barely goes below 65F before its called to start heating to meet a "I'm home" set point.  It appears yesterday though that it had to turn on once for about 5-10 min...shame.  Overall, my system doesn't even turn on until it's needed...so a set point of 65F works.
My next project will be installing XPS insulation on my crawl space walls and the rim joists.   My downstairs wood floors are pretty dang cold and insulating the crawl space walls and rim joists should significantly help it...at least that's what people say.   I'm still a little skeptical given that I feel like insulating the floors themselves would be best...although i guess insulating at the source makes sense too. 

A side note to this...I used my handy Black and Decker  thermal leak detector to check out the temperatures in the crawl space.  On a 26F morning...I found that my brick walls which are exposed to the air were somewhere around 38-41F (some small corners registered at 32F!).  Very cold!  The walls that were not exposed (i.e. underground) were 50-55F...so 10-15F warmer.   The crawl space air itself was 59F.  So apparently if I insulate the walls, while letting in a little HVAC air (just a smidgen) I can keep the crawl space significantly warmer which will make my floors warmer.

That should be fun.  When I finally get around to it, I'll post a bunch of pics to show how I did it and hopefully include results...unless we have another freakishly warm January/February like last year.

Monday, December 17, 2012

HTPC Upgrade


My Ubuntu Linux Mythtv Home Theater PC (HTPC)

Hey folks-

So I finally was able to get my Dad (aka...someone with Linux experience) to help me set up my HTPC for maximum power savings.   So what's a HTPC or Home Theater PC?  Think of a Tivo or Digital Video Reorder (DVR) that your cable company makes you pay for.  Except this is homemade, stores significantly more than just TV recordings, but also my movies, music, and pictures.  Well...it will eventually...in my last upgrade I still have slacked in moving my pictures and music back over to it. 

OK...so after my last upgrade, I was able to reduce my overall power usage from 120W to 95W.  I use the term "overall" because the power usage is not just the PC itself. I have the following additional equipment:
1)  Network switch for multiple ethernet using devices
2)  HDPVR to record TV off the cable box
3)  Crappy Cable Box from Time Warner Cable
4)  Signal Booster because I have to split the Cable TV signal 4x
5)  HDHomerun tuner to record my local QAM TV

I also have a remote frontend unit (think mini-computer) that allows me to stream everything from the main HTPC to the downstairs TV.  That unit is small and only uses 19W.   I had already setup this frontend to 'sleep' when I shut off.

Well...of course, for me, 95W running 24x7 was not acceptable.  So I emarked on the next level of upgrade.  Luckily, this was a software upgade, not hardware.  With significant help from my Dad, we setup the HTPC to shut down between recordings.  So, once a recording is finished and it's been commercial flagged, the system reviews when the next recording is upcoming.  If its a long enough time (20 mintues), it will shut down the PC.  It will not shutdown the PC if (a) someone is logged in (such as when I'm using it) or (b) if the downstairs frontend is running.  So it's not going to shut down right in middle of someone watching a recording. 

It took a lot of tweaks to get everything operating right, but it seems to be running well. I have since grabbed a smart power strip to shut down as many accessories as I can when the PC shuts down.  This is mainly the HDHomeRun and the HDPVR.  I tried to use the signal booster, but I found out that if the Cable Box reboots, then it can't connect/fully reboot until the signal booster is on.  And it takes frickin' 8 minutes to boot!  So if I want to start recording something right away, I can't do it because I have to wait for the box to finish booting. 

So, what has this done for me?  Well, I just plugged in the Kill-a-watt meter and I've gotten some preliminary results.  They are as follows:

HTPC Running with all accessories:  95W
HTPC Off with all accessories:  41W
HTPC Off with some accessories off:  29W

Accessory Power Usage:
Signal Booster:  3W
Network Switch:  3W
Cable Box:  23W

Before I go on a rant about my #$*&# cable box, this is showing a 67% reduction in "always on" power usage.  More than likely this will end up being bigger when we factor in operational time and start talking killowatt-hours.  I just started collecting data so I don't have official results...but let's talk about some theorectical values (not counting the frontend since its the same usage regardless):

Before (Operating 24x7):
95W x 24 hrs/day * 1 kWh/1000W = 2.28 kWh/day

After (Assumes used 4 hrs/day:
95W x 4 hrs/day * 1 kWh/1000W + 29W * 20 hrs/day * 1 kWh/1000W = 0.96 kWh/day. (58% Energy Savings)

What did this cost me?  Well...i did have to buy a new solid state hard drive (SSD) for my frontend so I the system could shutdown instead of 'sleep'.  This also significanly sped up the reboot to something like 10seconds and allowed me to write some code that when the frontend turns on, it 'pings' the HTPC to turn it on.  After it waits for the HTPC to boot (that takes 10seconds), then it connects and starts Mythtv. That cost me $57. 

1.32 kWh/day savings * $0.10/kwh * 365 = $48.18/yr.  So my ROI is 1.18 years.  Yeah, I'll take that. 

Now for that &*#$& cable box.  I can't believe it uses 23W!  And the sad thing is that when you 'turn it off', it doesn't save any energy.  Seriously!!!! I checked it with the kill-a-watt meter!  Not even 1W.  Why is this device sucking down this much energy?!? And to top it off...why the heck does it take 8 minutes to boot?  I TIMED THIS!  In the age of superfast computers that use little energy this is ridiculous!!!  My frontend computer uses less energy (19W) and is equipped with a 30GB SSD, a dual core 1.8 GHZ processor, and boots in 10 seconds.  And it probably decodes HD TV faster.  It certainly makes you wonder what the heck is going on with these companies.  I know my TWC service blows and I'm just waiting for the day that there is sufficient competition in NC so they will come out of the dark ages.  My only real alternative is AT&T and their "digital" internet service is nearly half the speed of TWCs.

OK...*pant pant*...calm down boy....off the soap box.

The long story short...this was a fairly painless upgrade that'll knock off some kWh's.  With my new fridge knocking off about 0.5 kWh/day, I'm reduced my baseload usage by ~1.8 kWh/day.  My 'always on' energy usage is down to about 165W (3.96 kWh/day).  There's a couple things I can do to get this down a little futher, but not much.   At least 85W of this power is the upstairs and downstair geothermal systems on standby (~30W each) and then the frickin' cable box (23W).  Then there's things like the alarm clocks, the internet cable modem, and the router.  Yeah...these are staying on.  However, it would only take 500W of solar capacity to completely negate this energy usage.  We'll see when that happens....

Wednesday, December 5, 2012

December 2012 Energy Results



(I felt like the blog posting was boring so I tossed in a pic to liven it up.  Here my recent TED5000 Monitored Usage)
Hello Readers-

I hope y'all aren't still not choking down thanksgiving turkey.   Not me...but my dog is eating like a King.  Although I still think there's some gravy left in the fridge.  And let me tell you....Gravy tots....MMMmmmmmm....just saying...try it.

Back to business...I got my latest Duke Energy Bill in and the results are posted below.  It's another year of savings which is good! 

To the numbers...

December 2011 Bill
Total Energy Usage:  963 kWh
Days:  30
Average Daily Usage:  32.10 kWh/day
Billed Amount:  $92.00

December 2012 Bill (Nov 1 - Dec 3)
Total Energy Usage:  970 kWh
Days:  32
Average Daily Usage:  30.31 kWh/day (5.57% reduction from 2011)
Billed Amount:  $98.52
Absolute Savings versus 2011:  - $6.52 (you can easily see the rake hike:  7 kWh total difference is not at $0.93/kWh)
Rate Adjusted Savings versus 2011 @ 0.1056/kWh):  $10.84 (lower winter rates now).

Overall, there has been a savings, albiet small.  One thing to note is the totally different temepratures between 2011 and 2012.  It was definitely colder this year than last.  To address this I looked up the heating degree days (HDD) for 2011 versus 2012.   I used NOAA monthly climate data for Charlotte, NC posted here.

For the same time period (Nov 1 - Dec 3) in 2011, we had 446 HDDs.  This year we had 533 HDDs which is a 87 HDD increase.  To put this into perspective, let's compare the energy usage to the HDD.

For 2011: 
Energy Usage = 32.10 kWh/day
HDDs = 446
No. of Days = 30
Heating degrees (HD) = 14.87
Energy Usage per HD =   2.16 kWh/HD

For 2012: 
Energy Usage = 30.31 kWh/day
HDDs = 533
No. of Days = 32
Heating degrees (HD) = 16.66
Energy Usage per HD =   1.82 kWh/HD  (15.7% reduction)

Overall, the climate adjusted energy reduction is around 15.7%.  This isn't uber-accurate given that I'd need to subtract out non-temperature related energy usage to get a more accurate representation...but I don't have that data.  Thus, I've made the assumption that my lights/TV/cooking/etc usage has not significantly changed since 2011. 

Saturday, November 3, 2012

November 2012 Energy Bill...Second lowest usage ever!

I'll tell ya...if I knew that changing out my hot water heater was going to make this big of a difference, I would have done it a long time ago.  Below is my energy usage information for the November 2012 Duke Energy bill:

November 2011 Bill
Total Energy Usage:  734 kWh
Days:  29
Average Daily Usage:   25.31 kWh/day
Billed Amount:  $73.20

November 2012 Bill (October 2 - November 1)
Total Energy Usage:  509 kWh
Days:  30
Average Daily Usage:   16.97 kWh/day (32.97% reduction from 2011)
Billed Amount:  $58.14
Absolute Savings:  $15.06
Adjusted Savings for Increase in Rates (@ $0.114/kWh):  $24.94

Recall in my October post, I noted that my previous low was in June 2011 where we used 526 kWh which equates to an average daily usage of 17.53 kWh/day.  So our November usage was again, lower than I previous low.  And last month, we had the heat on for at least half the month.

As for new projects, I posted about installing the Ecobee last month.  Following the data online, the system is certainly is maxing out the first stage, which is more efficient, as I want it to do.  

We also just bought ourselves a new fridge.  That will be installed next week and should reduce our energy usage by about 0.43 kWh/day.  Yeah...not a lot, but my fridge will bigger (it'll finally fit a platter) while still reducing usage.  And we got it $1500 cheaper (New @ Sears outlet + Energy Star Tax Weekend). I'm OK with that.

And I need to get back on the HTPC project.  I can get the PC to shutoff...but turning back on is an issue I'm still working on.  I did get myself a new router that'll allow me "wake-on-LAN"...which means it'll allow me to turn on the PC remotely when I want to say...set a new recording.  Again...this will take a while to figure out and I'm sure I'll require help from my Dad and Brothers as they are much more astute than I at Ubuntu Linux.



Wednesday, October 24, 2012

Ecobee Thermostats Installed!

Ecobee Thermostat Installed on my wall
I finally bit the bullet and bought the Ecobee Smart thermostats.  They were $260 each which wasn't too bad.  Installation was a little bit of a hassle. It was difficult because the instructions were not clear for my geothermal installation.  To me, it was not clear what Power went where. Below is a pic of the former Honeywell thermostat.
Pic of the wiring from the former Honeywell Prestige IAQ Thermostat
 Luckily, the Ecobee support team was great. I emailed them and they were very prompt in their response. We went back and forth a couple times (thank you Gus!) and eventually we found out that I only have 1 @ 24V power supply while the diagrams listed two supplies.  So I needed to run a jumper wire from one 24V input to the Ecobee to the other side of the control board.
Ecobee Control Module Installation.  I did clean the wiring up more after the pic was taken.
Once that was determined, it was a breeze.  The upstairs unit includes the flood sensor (the thick red wires on the bottom left in the above picture).  If the flood sensor registers a flood it will shut down the air handler AND will send me an email.  Pretty cool, huh?
Final Installation of the upstairs Ecobee Control Module.
Programming the Ecobee was very easy.  For the most part I kept the default settings that were recommended by Ecobee for a geothermal install (that was a menu option in the Installer Setup).  The only things I changed were the delta for when the system turns on/off and the Stage timing.  For the delta, I set it to be 1.5F instead of 1F.  For this I'm just sacrificing a little bit of comfort for more energy savings.  For the Stage timing, I set Stage 1 to run for a max of 2 hrs before Stage 2 turns on.  Stage 2 will run for 3 hrs before it calls for the emergency electric heat.  Thus, my system would have to run for 5 straight hours before it will call for the expensive, inefficient heat.  In addition, the system will stay on the most efficient stage as long as possible.

The web interface is pretty cool.  A pic of it is below.  I can pretty much change any setting I want from the portal.  And its generally much easier to do it here than on the thermostat.  Below is a pic of the thermostat settings.  The dark blue is "sleep", orange is "awake", green is "away", and light blue is "home".  So for Monday-Friday, the vast majority of the time is "away".  Then on weekends, I have more "sleep" and "home" time.

Ecobee Web Portal
 The only cool thing is that I can check out graphs on how my systems are operating.  I can see the setpoints, the indoor and outdoor temperatures, humidity and the system run time.  It's very cool.  The Ecobee site also produces monthly runtime reports and lets me know how my system is doing compared to other homes of a similar size and geographical location.  Since I've only had it installed for +/- a week I'll have to wait to show y'all the results of the report. 

Downstairs Themostat Operational Information

Upstairs Thermostat Operational Information
 The Operational data is all downloadable.  What would  be VERY COOL would be if I could link this system data with my TED5000 home energy usage data.  This would allow me to track exactly my energy usage from HVAC.  That's probably a task for someone smarter than I.

There's also a Android App that I use on my phone.  It essentially lets me change the temperature, turn the system on/off, check the weather or set a vacation schedule.  Below is a screenshot from the phone. I can easily switch between thermostats too.

Screenshot from Ecobee Android App
 What would be really cool would be if I could look at the Operational information from the App.  Right now the only way to to do it is to login to the website from my phone.  It's a little bit of a pain...but not too bad.


Thursday, October 4, 2012

October Bill - Lowest Month Ever! - 39% Reduction

Hi All!

I've been excited to see what this month's results would be and it really blew my socks off.  It was my lowest energy usage month EVER in the new house.  It even compares to the days when I was living in my former townhome (which was built in 2005 with gas heating, cooking, and water heating).   The results are below:

October 2011 Bill
Total Consumption:  771 kWh
Days:  32
Average Daily Usage:  24.09 kWh/day
Bill:  $79.75

October 2012 Bill (September 4 -October 2nd)
Total Consumption:  409 kWh
Days:  28
Average Daily Usage:  14.61 kWh/day
Bill:  $49.91
% Reduction in Energy:  39.4%
Bill Savings (based on current average rate of $0.113/kWh) = $37.36

So this bill breaks the previous record set in June 2011:

Lowest bill:  $49.91 vs $53.54...and this includes a hike in rates!
Lowest Monthly Consumption:  409 kWh vs 526 kWh.  While June2011 has 2 more days in the billing month, if we tack on another 2 days at ~15 kWh/day I'd STILL be way under (439 kWh vs 526 kWh).
Lowest Average Daily Consumption:  14.61 kwh vs 17.53 kWh

I mentioned my previous townhome which was building in 2005 (1,300 sf, gas heating, cooking, and hot water).  If I compare the usage there in the "swing months" where I wasn't using any HVAC, I averaged 14.3 kWh/day (~414 kWh).   Recall...my current home is 2,700 sf built in 1984 with electric everything.  So needless to say, I'm thrilled that I've done so great.

Kudos to the GE Geospring ASHP Water Heater which was no doubt, responsible for helping me significantly reduce my consumption.  And to think that half the month was without it too...

Next up...I ordered my new Ecobee Smart Thermostats.  Once those come in and I set them up I'll have my HVAC system as fully optimized as I can get it along with monitoring.  I'll give y'all the low down in about a week when they arrive and I install them.

Also, I'm working on getting the HTPC to shutdown and wake up.  I can do it manually, but I just need to figure out how to get it going automatically.  I'm not a big linux guy so it'll take a while for me to figure it out. This task alone should save me an additional 1.84 kWh/day (13%)

Friday, September 21, 2012

New Hot Water Heater - Preliminary Results

TGIF  Readers!
(At least for me at the time of my typing..)

I've got some exciting preliminary energy reduction results!  Recall that about a week ago I installed the GE Geospring hot water heater.  Well, I've been watching the days closely and tracking energy usage and wow has the new hot water heater (and combo crawl space dehumidifier) making a difference.  Below are the graphed results:



As you can see above after turning off the HVAC system and before installing the hot water heater, energy consumption was around 20 kwh/d.  If I was to go further historically, you'd see this a lot.  Even during my lowest month (Spring, No HVAC, vacation for a week), I averaged 17.5 kWh/day.

After installing the unit, my average has plummeted to 14.5 kWh/day.  And me and my wife are still at home...no vacations...doing the same things we do every week (laundry, cook, clean the dishes, shower, watch TV, etc).  That's a 6 kWh/day or 29.4% reduction in energy usage.

Note that this average ignores the day we actually installed the unit (9/8) because the unit had to reheat all the water so that's why there's that big bump (when it first turns on, the startup cycle uses the electric elements to get up to temperature fast).  Also, I needed to make sure everything was OK with the desuperheater/piping/preheat tank so I bumped on the A/C for a short period of time.

OK...so what does this all mean? 

Well, 6 kWh/day x 30 days = 180 kWh/month x $0.113/kwh = $20.34/month in savings or $244/year.  I'll take that.  It's not quite the 9.33 kWh/day of energy reduction I had anticipated, however, this is at a hot water temperature of 130F while the former HW heater was set at 120F.  Why so high?  Well, I read in the Geoexchange forums that if the desuperheater/preheat tank increases the HW temperature to above the Geospring set temperature (which it can in the summer), the Geospring will error out and need to be reset.  With summer behind us and the HVAC off, I'll put the temperature back down to 120F.  I should have done this earlier (since I turned off the HVAC even before hooking up the Geospring!), but I was trying to be conservative to start.  

So, here's another thing...even with the Geospring temperature set so high, I'm still seeing significant savings.  Overall, I'm recording energy usage days at all-time lows (10.7 kwh/day!) even though I'm home.   At the current rate, it's looking like I'll only use 534 kWh for this month (17.8 kWh/d).  My all time low is 526 kWh/month (17.5 kWh/d) and that was during the Spring of 2011.  Note that most Springs I'm around 500-600 kWh while during the fall I'm typically around 700 kWh (~24 kWh/d).   

So what's next on the chopping block?  Well, installing the Ecobee thermostats will wrap up my optimization of the heating, cooling, and hot water systems.  I'm not going to do that until temperatures drop and I actually have to use my HVAC system...so that'll be mid- to late-October, probably.

Then after that I'll start looking at my next two biggest energy users...the HTPC and the Fridge.  From my latest Kill-a-watt readings that Fridge uses about 1.9 kWh/day.  That's about 11% of my current daily usage.  At best, a new fridge will knock that down to about 1.2 kWh/day (0.7 kWh/day savings).  I'm not rushing this investment because the ROI is just not there.  However, I'm not fond of my fridge (too small...even for only 2 people!) so that's why its on the chopping block.

My Mythtv HTPC.

Then there's the HTPC.  One average the HTPC (and all its accessories) is using about 1.6 kWh/day.  I'm looking into how to get the HTPC to 'sleep' between recordings and then 'wake up' when I watch TV.  I'll need a new Wireless Router for this ($100), but besides that it's all software and time to get this going.  Once I figure it out, I should be able to reduce average daily power consumption by around 80%. My ROI?  About 2 years due to the cost of the new wireless router.

Combined the fridge and the HTPC could knock off another, roughly, 1.98 kWh/day...or 11% reduction.  That would put me down to about 15.5 kwh/day average daily usage (currently).  That's pretty dang good for a house that uses all electricity (no natural gas).  Getting lower than this will be very tough (stop using the dryer??)

Then there's looking at solar panels...but that's a whole another story...   



Monday, September 10, 2012

Repost: Ecobee Smart Plug


 Wow...this is sooo cool.  I'm totally going to have to loook into getting one of smart plugs when I get my Ecobee Smart thermostat.  Of course, I'd have to figure out what exactly I'd plug into it first.

Kudos to Chris @ mapawatt.com for this review:
http://mapawatt.com/2012/08/12/ecobee-smart-plug-review/


Sunday, September 9, 2012

New GE Geospring Hot Water Heater!

My new GE Geospring hot water heater in series with a preheat tank (not shown)

So I finally put in a new hot water heater.  As I had discussed in previous posts, I wanted a GE Geospring air source heat pump (ASHP) hot water heater.  Well, that's what I got.

Why am I so hyped about this?  Well for starters...

1)  The Geospring is rated at an energy factor of 2.5 which saves roughly 63% of the energy as compared to normal electric hot water heater (which I had).  On an annual average basis, my former HW tank was running 0.8 hrs/day @ 4.6 kW for 3.7 kWh/day.  Thus, this is expected to be reduce to 1.37 kWh/d.  

2) I had mentioned in some of a previous posts, that the geothermal supplemental hot water generator (desuperheater) really is not optimized when using one tank.  I'd read some forums that even claimed it could be costing me energy with calls for geothermal system manufacturers to remove the 1 tank setup from its installation procedures.   Well, this new hot water tank was connected in series with my "old" hot water tank (now un-powered).  The "old" tank will act like a preheat tank allowing for maximum hot water generation via the desuperheater.  This preheated water will feed the GE Geospring.  So overall, the energy required for hot water generation is cut substantially.

3) The Geospring is so efficient because its an ASHP hot water heater.  Essentially that means its an air conditioner connected to hot water heater.  So it will "condition" (remove heat and humidity) the air and instead of discharging the heat outside, it takes the heat and pumps it into the hot water tank.  Why does this benefit me?  Well, recall I've been using a dehumidifier in my crawl space to reduce moisture...and its been a fairly large energy consumer.  Well, the Geospring will now take the place of the dehumidifier by simultaneously conditioning the air (removing moisutre) as it heats the hot water.  Thus, I'll hopefully be able to negate using the dehumidifier entirely! That should save me somewhere around 7 kWh/day alone.

Overall, I'm hoping this work will reduce my overall power consumption by about 9.33 kWh/day.  It could be higher including optimization of the desuperheater, but I have not way to quantify this yet.  Even at 9.33 kWh/day this is about 280 kWh/month!  If you consider that in the last year (Sept 2011 - Sept 2012), I've averaged 853 kWh/month, then the 280 kWh/month will result in a roughly 33% reduction in consumption!  That equates to roughly $31/month.    This project cost me about $1200 to install, so that's a 3.19 ROI (not assuming any rate increases).  I'll take that... Only time will tell what I actually achieve...   

 

August Energy Savings = 18.5%

The August Dook Energy Bill is in.  The results are good!  See below:

August 2011
No. of kWh Used:  941 kWh
No. of Days:  31
Average Daily Energy Consumption:  30.35 kWh/d
Bill:  $90.95

August 2012
No. of kWh Used:  816 kWh
No. of Days:  33
Average Daily Energy Consumption:  24.73 kWh/d
Energy Savings vs 2011 = 18.54%
Bill:  $91.17
Bill Savings (converting 2011 Bill to 2012 rates) = $13.97

Still Looking great!  My 2012 average savings is 26.10% (36.7% not looking at the fringe seasons)

Tuesday, August 14, 2012

July Energy Bill - 20.33% Savings over 2011

Update:  I just noticed this was labeled June, not July.  I've updated this post with the correct information.  Sorry for any confusion!

My dook energy bill came in yesterday and below are the results:

July 2011
Total kWh:  888
No. of Days:  28
Average Usage = 31.71 kWh/d 
Bill = $86.97

July 2012
Total kWh:  758
Days:  30
Average Usage = 25.27 kWh/day
Bill = $85.62

% Reduction from 2011 = 20.33%
Bill Savings:  $1.35

While this looks great, I need to preface that I went on vacation for 10 days so there's no doubt that has an effect on my total usage...especially since June was VERY HOT. 

Y'all may have noticed that I put in the bill savings too, but that isn't a good indicator given that rates have increased over 2011.  The way to think about the difference is rates is to do the simple math:

2012 Cost per kWh:  $85.62/758 = $0.11295 (say $0.113/kWh)
2011 Cost per kWh:  $86.97/888 = $0.0979/kWh
Increase in rates:  15.4%

July 2012 Bill if still at 2011 Rate:  758 kWh * $0.0979/kWh = $74.21.  Savings compared against 2011 if still at 2011 Rate:  $12.76. 

OR 

July 2011 Usage at 2012 Rates:  888 kWh * $0.113/kWh = $100.34.  Savings compared against 2012 based on 2011 Usage = $14.72

I'm sure we could play with the math more and create other ways to look at it, but I'll stop here.  To-the-Point:  We saved energy and money. 

Monday, August 13, 2012

Radiant Barrier



Radiant Barrier in the attic
 So last weekend, I teamed up with one my friends and installed a radiant barrier in both our attics.  It was a fairly easy project.  His attic has gables and a single gable mounted attic fan (no soffits), so we put the radiant barrier directly over the insulation.  In my attic (has soffits and attic fan), I had a contractor install  ridge vent and then I stapled the radiant barrier to the joists except for the small attic space over my bonus room, where I installed the radiant barrier over the insulation.
 
Like I said...it was an easy project.  Luckily, it was cool outside so we didn't kill ourselves, although I did sweat up a storm.  Above the attic duct work (which is high) we "tented" over it to keep the heat away.  I used atticfoil.com for the radiant barrier.  It was a good product and i have no complaints.


Looking at the top of the attic.  You can see my high duct work and the "tent" over the top
 I can't say for sure how well it is doing, although today when I came home after a hot day (sunny and a high of 91F),  I noticed for the first time since I can remember, the attic fans  were not on when I walked upstairs and the temperature was 82F (thermostat set at 84F).  Nearly all summer when I came home the upstairs temp was 84F and the HVAC was cycling.    We'll see after August and September.

Monday, July 30, 2012

June Energy Usage

Sorry for the delay!  My wife getting the ebills and not a paper bill means I don't get the energy data as fast as I'd like.  Not to mention I went on vacation.  Below are the energy results from June

June 2011
Total Power =  1086 kWh
No. of days = 33
Avg Power/day = 32.91 kWh/day

June 2012
Total Power = 663 kWh
No. of days = 29
Avg Power/day = 22.86 kWh/day

Savings compared to 2011 =  30.53%

So, it looks great.  However, I'm not getting too excited given that that May was fairly cool and so far we've been sweltering this month.  

Saturday, June 30, 2012

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!

Tuesday, June 26, 2012

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:
EnergyDayskWh/dBillRev BillSavings
     
06/01/1110863332.91103.1471.5831.56
07/01/118882831.7186.9760.3626.61
08/01/119413130.3590.6562.9127.74
09/01/117713224.0979.7555.3518.30 (Red by 25%)
total104.21per year
2011 Winter Heating Bills:
EnergyDayskWh/dBillRev BillSavings
11/01/119633032.109286.545.46
12/01/1113183339.94121113.827.18
01/01/1210752937.07103.1897.066.12
02/01/1210512936.24107.9101.506.40
total25.17per year
Estimated Total Annual Savings129.37per 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.