# Am I stupid for not having a digital thermostat??



## wahoowad (Sep 26, 2006)

OK, I have been living in my home (my first home) for 9 years. I still have the original non-digital thermostat control that came with my heatpump. My heatpump is still doing OK but I have read several places that a modern after-market programmable thermostat will do a better job. I don't want to waste my money though. I'm assuming they are easy to hook up - just a couple control wires, right? Are the $50 - $60 units I see at Home Depot worth installing?


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## michaelthomas (Sep 26, 2006)

I have 4 zones in my house, 2 of which are regularly lived in.  I have digital programmable thermostat on those 2 zones.  It allows you to heat when you need it for instance...my wife gets up to workout in the family room @ 5:30 AM I program the heat to kick on to 65 degrees at 4:45 am.  When the wife comes down it is cozy warm (there is no woodstove heat that makes it to this room).  We all leave the house by 7:30 so I program the thermostat to go down to 55 degrees at 7:00 and come back up to 65 degrees about 45 minutes before we come home so it is cozy upon our arrival.  There is no need to remember to turn the heat down or wait for it to warm up once you come home.  At night I have it kick down to 55 degrees after the kids go to bed at around 8:00.  I love it and feel that we are saving fuel by only having it come on when we are home and need it.  I got mine at ace for close to $40.


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## wahoowad (Sep 26, 2006)

I have a single zone unit. In fact, my heatpump sucks but "should I replace my heatpump" is another thread. Anyway, I'm thinking the best a programmable thermostat will do me is:

- let me automate when the temp should go up or down based on my preferences;
- automate a different schedule for weekends when I am home all day compared to being away from home on weekdays;


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## DonCT (Sep 26, 2006)

I would recommend a programmable. I have a heat pump as well.

I bought one of the 7 day programmables from Home Cheapo. You just need to make sure that it's compatible with a heatpump w/ aux heat. That's very important. The one I bought is the RiteTemp 8050c. I can set individual day temps up to 4 time frames. It allows you to just copy programming from 1 day to the next. And it has a SDP (Special Day Programming) function. Basically that allows you to have a set point (say 72) incase you need to stray from the programmed temp. Very usefull if you or a family member is going to be there unplanned. I will stay at that setpoint till the next programmed time frame, then switch back to regular programming.

Looking at my heat bill from last year, compared to the year before, it definitely paid for itself over the original maunal tstat.


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## DonCT (Sep 26, 2006)

Link to the one I purchased:

http://www.ritetemp-thermostats.com/8050C.html


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## paulgp602 (Sep 26, 2006)

Look for a digital programmable that has a feature called "Adaptive Recovery". What this does is it learns how long your heating or cooling equipment takes to reach your desired temperature at wakeup or return from work schedules. For instance:
 My old thermostat was programmable, but didn't have adaptive recovery. I get up at 5am, so I used to set it to heat to 70 degrees around 3:30am. I assumed that it would take an hour and a half to heat from the sleep setting of 60- causing the boiler to run longer than necessary to reach a desired temp.

With adaptive recovery, the thermostat "learns" how long it takes for your heating/cooling equipment to reach the set temp, and runs the heating/cooling equipment just long enough to reach the set point.

Now my furnace kicks on around 4 - 4:15am~ ish to reach my wake temp, instead of the old t-stat's 3:30am setting. The adaptive recovery t-stat constantly records the previous day's cycle time and adjusts accordingly the next day. Check out Honeywell's line. The better ones offer this feature and it saves oil/gas for sure.


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## elkimmeg (Sep 26, 2006)

A forced  hot water syster statistics have proven that t an 8hour set back up to 7 degrees saves money over 7 degrees one looses all they think they are gaining to bring the home back to the 7 degree plus temp Satistics have also proven it is better to cut it 2 to 4 degrees rather than yo yo efect more enegry is saved. 10 degress swings wast too much energy to recover

 Forced warm air systems the set back sweet spot is 8 to 9 degrees. My info was taken from studies done by the EPA.   

 For example if one can live at 68 dregees   more energy is saved by keeping a constant 65 degrees in stead of the yo yo effect of setting back to 60 then to 68. Then let you wood/ pellet coal stove make up any difference. Its not bad to wear a flanel sweater or swetshirt.  at 65


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## michaelthomas (Sep 27, 2006)

elkimmeg said:
			
		

> A forced  hot water syster statistics have proven that t an 8hour set back up to 7 degrees saves money over 7 degrees one looses all they think they are gaining to bring the home back to the 7 degree plus temp Satistics have also proven it is better to cut it 2 to 4 degrees rather thasn yo yo efect omoe enegry is saved. 10 degress swings wast too much energy to recover
> 
> Forced warm air systems the set back sweet spot is 8 to 9 degrees. My info was taken from studies done by the EPA.
> 
> For example if one can live at 68 dregees   more energy is saved by keeping a constant 65 degrees in stead of the yo yo effect of setting back to 60 then to 68. Then let you wood/ pellet coal stove make up any difference. It ids not bad to wear a flanel sweater or swetshirt.  at 65



So keeping the temp when we are home at 65 and when asleep or away drop to no more than 57 degrees for optimal savings?  What about if 3 of the four zones in the house are covered by the wood stove and the furnace almost never gets a call from those thermostats and you have a system designed to heat 3000sf but you are only really using the furnace to heat one zone consisting of 600 sf room.  Would the load on the system be the same?  The burner only fires at one speed, all out.  What are some of the variables associated with the 7 degree money zone?  If I am truly only using my furnace to heat 1/3 of my house should I get a smaller nozzle on my burner?  Just some random questions


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## wahoowad (Sep 27, 2006)

I bought a Honeywell (7400D?) with the adaptive circuitry. I had to step up to that model to get one that could handle the auxiliary heat that comes with my heatpump. Good info for me to check on that! I was going to walk out of Lowes with the $29 model until I realized it wouldn't kick in my aux heat if needed.

I haven't even used my heatpump this year - no need for heat yet. I dread when she does start though. More for the noise than the cost. I have a noisy unit and a noisy air handler, and the house was built by some cheapskate builders who didn't design anything right. You learn a lot with your first house.


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## DonCT (Sep 27, 2006)

I hear ya about the heat pumps. Mine is the original from 1989 when my place was built. It's coming up on end of life and it's starting to show it's age. It's very inefficient, especially with the winters we have here in New England. Once the temp gets below 32, mine runs almost exclusively on auxiliary heat (which basically turns the air handler into a big toaster oven). As temps got even lower, the aux heat couldn't even keep up. Last winter, I could never get my place above 68 even with aux heat running almost 24/7. Those were some scary electric bills.


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## begreen (Sep 27, 2006)

Sounds like you'll be burning a lot more wood this winter Don.


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## DonCT (Sep 27, 2006)

Darn tootin!! My air handler/heat pump haven't ran since our last heat spell in July.

No more $400 electric bills for moi


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## wahoowad (Sep 27, 2006)

I got you beat Don! I'm running on my original and she's from a 1987 install (Rheem). The heatpump man who services her says it still isn't cost effective for me to buy a new system as this one is still working well enough. Barely. My living room (at the far end of my duct runs) will be 61 in the mornings, probably due to the many windows, double doors, vaulted ceilings and slab floor. A lot working againts me. That room is not an issue when the woodstove is running though!


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## senorFrog (Sep 27, 2006)

Is there a type of programmable thermostat that will not work off a temperature?  I want to use wood stove as much as possible, especially at night.  On one occasion in the past my pipes have froze because wood stove was cranking and heating system didn't kick on all night.  I'd like something I could program to come on, say...every six hours and run for five minutes.


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## Metal (Sep 27, 2006)

The fuel required to reheat a home to a comfortable temperature is roughly equal to the fuel saved as the building drops to the lower temperature. You save fuel between the time that the temperature stabilizes at the lower level and the next time heat is needed. So, the longer your home remains at the lower temperature, the more energy you save.  

The "smart recovery" thermostats are best for heatpumps because they begin heating early enough to minimize electric strip heating (expensive).


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## Rhone (Sep 27, 2006)

Elk, that's a misconception about turning it back only a few degrees else it causes your furnace/boiler to work harder.  Anyway, here's the US Department of energy's report on programmable thermostats where they mention 





> You can save around 10% a year on your heating and cooling bills by simply turning your thermostat back 10°–15° for eight hours. You can do this automatically without sacrificing comfort by installing an automatic setback or programmable thermostat.
> 
> A common misconception associated with thermostats is that a furnace works harder than normal to warm the space back to a comfortable temperature after the thermostat has been set back, resulting in little or no savings. This misconception has been dispelled by years of research and numerous studies. The fuel required to reheat a building to a comfortable temperature is roughly equal to the fuel saved as the building drops to the lower temperature. You save fuel between the time that the temperature stabilizes at the lower level and the next time heat is needed. So, the longer your house remains at the lower temperature, the more energy you save.



That makes sense in another way, cycling on/off is inefficient.  It's more efficient to have your furnace/boiler shut off for 8 hours and then have to run for an hour to get things back up to temp than it is to have your boiler shut off for 3 hours, then cylcle on/off maintaining a warmer temp (and you losing more heat), and then come on for 20 minutes to get back up to temp.  The article in that link talks about heat pumps, and how they need to run a particular way to be efficient which the old programmable thermostats didn't handle and nullified any savings.  That could be what was discussed by the EPA,  that article states todays programmable thermostats are smarter and the ones compatible with heat pumps compensate on recovery using an algorithm so as to minimize electric element use.  They let even those with heat pumps save $ on heating with a setback thermometer.  It sounds like wahoowad got the right one. 

*EDIT*  Just noticed Metal beat me to it saying the same thing.


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## Rhone (Sep 27, 2006)

senorFrog said:
			
		

> Is there a type of programmable thermostat that will not work off a temperature?  I want to use wood stove as much as possible, especially at night.  On one occasion in the past my pipes have froze because wood stove was cranking and heating system didn't kick on all night.  I'd like something I could program to come on, say...every six hours and run for five minutes.



You'd need an 8 period one to do it every 6 hours, the highest I've seen is 6 periods.  That means, you can have it run for a certain amount of minutes but only up to 3 times a day.  To do it, go to http://www.homedepot.com and do a search for GPMG8085C which should be a RiteTemp $79 programmable thermostat.  Then, you can set 6 periods or basically 3 blocks of times.  Something like the following will be close to what you're looking for

11:30 PM go to 100F (the thermostat will detect you're under set temp and start the heating system to start warming)
11:40 PM go to 58F (it now detects the temp is below and shut the heating system off unless your house is under 58F) 

4:00 AM go to 100F 
4:10 AM go back to 58F

9:00 AM go to 100F
9:10 AM go to 58F

Or, simply set the times & temps so it runs for 10-15 minutes every 8 hours or so.  **IMPORTANT*** You don't want one of the smart ones that has "Adaptive Recovery" that paul mentions and figures out how quick it takes to heat your house and compensates.  Otherwise you will have a 100F house.  You just want one that detects it's too low and turns on the heating system, then detects it's above so shuts it off.  I believe the one I show does not have Adaptive Recovery.


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## saichele (Sep 27, 2006)

The key point in this discussion is that you need to have a prolonged period when you're prepared to cut the heat back.  If everyone's at school/work during the day, or you're prepared for some snuggling at night, then it makes sense.  But our house is occupied most of the time, so I just leave the thermostat at about 63.  If the stove is going, it won;t kick in.  Just cold mornings or if the fire goes out.

Steve


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## Sandor (Sep 27, 2006)

Steve said:
			
		

> The key point in this discussion is that you need to have a prolonged period when you're prepared to cut the heat back.  If everyone's at school/work during the day, or you're prepared for some snuggling at night, then it makes sense.  But our house is occupied most of the time, so I just leave the thermostat at about 63.  If the stove is going, it won;t kick in.  Just cold mornings or if the fire goes out.
> 
> Steve



Exactly!


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