Thermostat setting questions: efficiency question

Grayguy

I'm not sure if this should be here or in general, so mods I apologize.

I recently installed a digital programmable thermostat in my house and It has led me to a few questions. The factory settings for the heat adjustment had it going from 64F all night to 72f in the A.M. That seems like a large gap to me. From an efficiency stand point, aren't you just going to burn all (or more) of the oil you saved by lowering the temp all night trying to heat the cold house back up in the AM? What is the most temperature variance you can use while still being as efficient as possible?

HVACTECH96

I suggest no more than 5 deg setback based upon homeowner feedback.I know there is a percentage of savings for every degree, but I cant remember that figure right now.I've had homeowners tell me they have tried both setting back and keeping at one temp, and not showing any difference in gas usage.

bob22

Government says:"You can save as much as 10% a year on heating and cooling by simply turning your thermostat back 7°-10°F for 8 hours a day from its normal setting."
However, they've some comments on HEAT PUMPS, ELECTRIC RESISTANCE HEATING, STEAM HEAT, AND RADIANT FLOOR HEATING systems:
http://energy.gov/energysaver/articl...ontrol-systems

gregzoll

I decided this year that instead of going from 69 to 62, to set to 65 at night and away. Summer, we keep it around 72, since the system runs more efficient with a/c, since you are not placing a large heat gain on it.

Only time that I would set to say 60 in the Winter, or 78 in the Summer or maybe 82, would be when you are away on vacation. People have this false sense of security, that the more they setback the thermostat, the more they will save. In turn they are wasting money, because they do not fully understand how the house/apt/structure works along the hvac system.

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TheBobmanNH

I'd say trial and error on this one, but... for my money, the lower the better (within reason). If your house is going to drop 10 degrees overnight, your heating system would have had to have been running to try and maintain that temperature all night, rather than just running once in the morning. Seems like a no-brainer to me.

jagans

The fact is that the hotter you make it inside the more pressure there is trying to equalize the indoor and outdoor temperature. In other words its not a straight line differential. I have found over the years that setting the night temperature to back to 65 degrees at 11:00PM, and 68 degrees at 5:00AM (About a half hour before we get up) has several advantages:

1: Less sickness. Hot air dries out your nasal passages, and you get up like you have a damn hangover.

2: Efficiency: You burn less fuel.

If somebody wants it hotter than 68 degrees, tell them to put on a sweatshirt, or run around the block to get some exercise.