Thermostat settings

[tim79]

I had a customer ask me if her husband is saving money by leaving the furnace at 62 while at work, than turning to 70 when arriving home. She thinks it should be left at 70. I was unsure how to answer cause she has a new furnace with a ecm motor, and sided with the husband half heartedly since system would be off for 8 hours during the day. What do you all think.

[54regcab]

The husband is right.

[cehs]

6-8 degrees MAX. change, summer or winter....

[beenthere]

The husband is correct.

[54regcab]

6-8 degrees MAX. change, summer or winter....

Not true with Gas Furnaces. With gas furnaces, the more setback the better. Setting it warm enough to prevent the pipes from freezing is all that's needed. My Furnace can take my house from 50 to 68 in about 30 minutes.

[2sac]

Tell her to go get a job and she won't have to worry about it.

[kamersoutdoor]

Not true with Gas Furnaces. With gas furnaces, the more setback the better. Setting it warm enough to prevent the pipes from freezing is all that's needed. My Furnace can take my house from 50 to 68 in about 30 minutes.

Not in disagreement, but with a properly sized system wouldn't 6-8 make more sense?
Or at least would it not depend on certain circumstances? I.e. 2 stage vs ss, 90+ vs 80%
Or insulation/age of home make a difference?
I'm probably wrong here, but curious at the least!

sent from my Samsung Galaxy Note

[54regcab]

Not in disagreement, but with a properly sized system wouldn't 6-8 make more sense?
Or at least would it not depend on certain circumstances? I.e. 2 stage vs ss, 90+ vs 80%
Or insulation/age of home make a difference?
I'm probably wrong here, but curious at the least!

sent from my Samsung Galaxy Note

Absolutely, correct sizing with less setback makes the most sense. Unfortunately gas furnaces are typically sized at twice the size needed.

[mav2909]

I have seen utility usage data that supports only about 5 degree setback for times longer than 6 hours. ie, dont set it back more than 5 degrees and only if your going to be away for more than 6 hours.

[samejj]

i smell a repeat customer.... if only we could say what we think.

[must]

whoever is bringing money home and paying for furnace is right.
what i think is 7- 8 degrees setback is right thing to do

[lash61101]

I agree with the 8 degree difference. I usually set it to 64 degrees and 68-70 when arriving home after work.

[tedkidd]

For anyone claiming setback saves, I ask how much? 2 cents a day? 20?

Please prove it. I'm dying for someone to prove it. Prove it on a decent house with decent equipment, not a crappy house with crappy equipment and 4 windows open. I don't believe the savings, IF THEY EXIST, are MEASURABLE much less MEANINGFUL.

Look, you guys are some of the thought leaders. Please take a step back and question this bad dogma.

If you don't measure both ways you are guessing. Every house and the equipment therein are so different, that to know whether setback saves, does nothing, or even COSTS MORE is an unknown unless you actually test.

I believe setback is a complete myth, "world is flat" dogma blindly fed to us and followed without thought. So deeply engrained, even after rejecting it I have trouble fully shedding myself of the inclination to fiddle with my stat.

I believe Setback Dogma actually has many serious hidden costs, including being responsible for the problem of grossly oversized equipment (anybody think there is no energy cost there?).

Here's a paper I wrote:

http://bit.ly/energyvanguardsetbacksucks

The premise is free energy savings at no cost? Bullcrap. The interior temperature has to be much higher if you allow surfaces to go cold. Mean Radiant is critical to comfort: http://bit.ly/comfortcalculator

No cost? Bullcrap, rot and mold aren't free:

Figure 10: Uncontrolled air flow moving from the inside to the outside creates all sorts of problems. One of the more common issues with the outward flow of warm moist air is condensation. Should air with sufficient moisture come in contact with a surface of a suitable cold temperature it will condense. Condensation on windows is a visual indicator of what could also be occurring within the wall, floor and roof. You can smell the problems with musty odours and see the results of this with mould and mildew, staining and ice dams at roof edges. Sometimes all it takes to create condensation is the use of a setback thermostat...

http://bit.ly/HHhpOverview

I'm seeing people abandon setback and save money. We need to be the thought leaders on fixing this 20th century approach to "saving", it needs to be removed from the current lexicon.

The earth is no longer flat, and that thinking is actually harming people and impediment to our industry's ability to do really good work.