Programmable Thermostats (furnaces, heaters, costs, warm)

[Omaha Rocks]

I just programmed the thermostat in my office building for summer cooling.

On the instruction manual for this particular thermostat, there is this claim: "Studies conducted by the Department of Energy estimate that setting your thermostat back 10 degrees for two 8-hour periods during winter can reduce your fueld bill by as much as 33%."

This has me thinking thoughts I've thought before...

First of all, the wording is pretty nebulous. Words like "estimate" "can" and "as much as" leave the door open to some pretty lofty sounding numbers, without having to really be honest.

Second, what are your thoughts regarding programmable thermostats? Are they really that good? Do they do what is promised, or are they a waste of time and money?


I have a programmable thermostat at my office building, and at the house my family lives in. I have a regular thermostat in our rental house.

I think we save a little money at the office building, because I leave the heat turned way down from 5:00 PM until 6:30 AM.

However, I stopped using the programmable thermostat at home. Ours is a big old 2-story brick house, with wide woodwork and plaster. It seems to me that once the plaster is warm, it's best to keep it that way. But once it gets cooled down 10 degrees, it takes forever to warm it up. I've noticed no significant change in our heat bills.

That said, both houses and my office building have new high-efficiency furnaces, so we're doing pretty well anyway.


What are your thoughts & experiences with programmable thermostats?

[CptnRn]

Yes, it should make a significant difference. It is a physical law that the rate of heat transfer from a warm interior space to a cold exterior space, increases with the difference in temperatures.

Newton's law of cooling, states that the rate of heat loss of a body is proportional to the difference in temperatures between the body and its surroundings, or environment

.

http://en.wikipedia.org/wiki/Heat_transfer

[M3 Mitch]

The less cold it is, the more % you will save on heating with a setback. Assume you set back from 70F to 60F overnight and the overnight low is say 50F. Probably the heat won't come on at all.

The only time you can lose money setting back a thermostat is if you set way back on a heat pump *and then* turn it up far enough/suddenly enough that you use the "backup" heaters rather than just the refrigeration loop to heat the house.

The claims on the thermostat are more than just hand-waving, but they are based on averages nationwide on typical construction, typical climate, typical power costs, etc.

[Cattknap]

Maybe you need a more efficient furnace - 90% or 95%?