Learning Thermostat - a huge impact on Energy Savings

Ok, I have had a couple programmable thermostats in the past... But, once again about 11 months ago I was doing my weekly (sometimes daily) stroll through the neighborhood 'big-box' home improvement store and back in the back past the garden section there is this little end-of-aisle display with a video playing and there is this neatly packaged 'Nest'.

And, I am intrigued enough to drop $250 USD on a thermostat. Again, another purchase on the fly with no pre-planning or research. And well, I was and continue to be VERY pleased with my Nest Learning Thermostat.

With my many Home Energy Conservation projects in our our home this past 18 months. I cannot quantify objectively how much impact the thermostat has made to our significantly reduced energy bills. But subjectively, I can honestly say it has been huge~!

Most importantly, and unlike my previous 'programmable' thermostats, I use this thermostat - more than passing down the hall and turning up or down the A/C-Heat. I am not standing in the hall with a head lamp and magnifying eye-glasses trying to thump-stumble with dip switches and obscure menus to 'program' my Nest.

I can program my nest from my Mac (PC), my smart phone and/or iPad. Mostly, I use my smartphone. It is an integrated part of our weekly life. I challenge myself to attain daily 'green-leafs'. The daily history is very nice to see.

The thermostat uses its motion sensor to set its state to  'Auto-away'. You can also easily, while heading out the door, set the thermostat to 'Away'.  With the wifi capability and from your iPhone/iPad you can change the 'Away' to 'Home' and set the thermostat temperature on your way back home to arrive at a  pleasantly adjusted home. Leave home for the weekend and forget to adjust the thermostat? No, problem. Auto-away will take care of it or you can turn off your A/C in Texas while setting in NYC.

It is simple and intuitive to use~! Very well worth the $250 USD I invested. I know that in the Texas summer my A/C electric bills saved me the $250~! Honestly, I can say this is the best $250 I have spent this year.

And, it wins my aesthetically cool meter - Form, Function and Fit~!

Background:

I am in the middle (hopefully, 90% complete) with various Home Energy Conservation projects in our 2,000 sq. ft. North Texas (Plano) home - R30 Attic Insulation, Radiant Barrier attic foil, attic Breeze solar attic fans, new windows, LED Lighting Replacement, etc... And, to share my trials and tribulations.

Project Cost:

$250 

Project Completion:

May 2012

Project Duration:

25 minutes

Views: 1062

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Comment by Tom DelConte on April 12, 2013 at 5:21am

Bob/Ted You two infer a great point! There's no sense getting into a smart thermostat that is not highly integrated into the local utility co. PECO/ Exelon has nothing like that here due to the fact that 20% of the people in PHL(philly) do not pay their bill on time, and due to the slow rollout of smart meters. Some of these have caught fire, slowing the program further.

OK. the hidden effect of thermal mass is slower temperature changes. You really only want to heat or cool the air, then do makeup as the mass slowly exchanges heat with its surroundings. Thermal mass only works for passive solar heating, or for limiting overheating in summer.

People just love to use the term thermal mass without understanding the thermo. of it all. I'm currently tearing out tile floors and stone countertops to minimize thermal mass effects.

Pre-cooling is always going to be relative to the area's rates, and the 'human family demand' for an immediately cool space once they enter it!

Comment by Bob Blanchette on April 11, 2013 at 6:21pm

Tedkidd I experimented with that last summer, but haven't collected enough data to have any conclusive results. Our house has a lot of mass relative to it's size, so "precooling" may end up being an effective strategy. Using 4KWH during off peak rates would only need to save 1KWH @ 20 cents per KWH during peak to be effective. The problem comes in the programming of the thermostat, since each day has a different peak price. Precooling may not be effective @ a 9 cent peak, but would probably be worth it @ a 44 cent peak.

Comment by tedkidd on April 11, 2013 at 6:14pm

Be interesting to see what driving temps to 72 in the hours before the price jumps does to both cost and comfort.  

Comment by Bob Blanchette on April 11, 2013 at 5:38pm

The website only shows a line for the temperature vs time of day/year. I can pull KWH and cost per hour/day/month/year. It doesn't state how much of the $147 savings was from reduced AC use during the 2-7pm weekday peaks, but since the AC is the big user during those hours I suspect it's where most of the savings comes from.

The thermostat can be programmed to increase the temperature during the peak times by a user defined amount. For example when rates are 5 cents per KWH I have my thermostat set @ 75. During a 9 cent per KWH peak I have the temperature go up to 77, at 20 cents I have it go to 79, at 44 cents I have it go to 85 which is basically off. OG&E is limited to 80hrs per year at the 44 cent rate.

Comment by tedkidd on April 11, 2013 at 5:27pm

Very cool.  I want that!!

How about temperature overlays, etc...  Think of all the cool analytics they could potentially come up with. 

Comment by Bob Blanchette on April 11, 2013 at 4:51pm

Comment by tedkidd on April 11, 2013 at 8:54am
Comment by Tom DelConte on April 11, 2013 at 8:03am

@Bob- please show us your myogepower reports like the way Ted Kidd showed his thermostatusitis reports! [I have no deluxe reports to share- just old equipment that keeps running due to trick ways of fixing it]

Comment by Bob Blanchette on April 7, 2013 at 9:57am

Apparently SilverSprings already wrote up a report, here it is:

http://www.silverspringnet.com/article/silver-spring-networks-showc...

Comment by Bob Blanchette on April 6, 2013 at 6:30pm

I might just do that when I have the time to get the writeup done. The average customer on the program saves $200 over a summer, so it definitely works on a large scale. The Variable Peak/Time of Use pricing is key element of the program. Without it, savings wouldn't be nearly as much. IMHO if you have TOU or VPP rates setback thermostats can make a lot of sense. With flat rates and well insulated/sealed/high mass buildings not so much.

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