thermostat setback

mac_3

how well your homes thermal shell is combined with the type and responsaiveness of your radiation.

Dan spoke once of the "pick-up factor": if everything in the room/house dropped down to 60*F, you'd have to send enough heat in for all the furnishings etc to absorb that energy before the ac tctual space temp come s up. Of course, a fast response scorched air system will seem to bring the space temp up quicker, but as soon as the blower is off...say, its cooled off again in here! Hydronic system w/constant circulation and outdoor reset will provide best savings assuming its not a monster house with areas shut off for long periods of time..

Sorry for the ramble!


mac

Dan_52

thermostat setback for optimal energy saving

I have two programmable (Honeywell) thermostats. They are set to turn the heat up to 68 degrees at 6AM then 50 degrees from 8AM then back to 68 degress at 8PM.

I read somewhere that the greater the setback, the greater the savings, so I turned it down to 50 degrees. Then I was told that I was setting back too much and was actually using more energy to heat the house. I was told to set back 8 degrees maximum.

What is the optimal setback??
My heating bills are quite high even with new windows and insulation.
thanks
Dan

Unknown

According to...

a study done by Honeywell many years ago 4* was determined to be optimum. The thought being any more than that and you spend any money you saved, and maybe more, warming back up in the morning. This is especially true for heat pumps that use electric backup. Set back too far and you will turn on the electric heat to catch back up when you come out of the setback. Running the electric heat unecessarily is bad for efficiency, real bad. I probably wouldn't set a HP back more than 2* but that's just my opinion. Plus, I've found that when there's too much of a setback the mass in the space (furniture, walls, etc) will not warm up to room temp all day and will tend to make people feel chilly even though the actual air temp says otherwise. Dan calls it "Cold 70" because even though the air temp may be 70* the cold mass in the room sucks the heat right out of you and you will feel cold.

My example, a bank where they turned the heat off all night. The girls froze all day even though the air temp was 70* and they all had little heaters under their stations. Contact temp of the granite teller counters showed 56* at 3 pm. I limited the setback to 4* and after a couple of days, to give the mass a chance to catch up, the girls were warm and the heaters went away.

bruce_21

There are some setback stats that are made to inch up the heat slowly to keep the electric back-up from coming on. I'd check with Honeywell to see what yours are designed to do.

Unknown

Good to know...

cause I didn't. I'll check into that myself. thanks!