Anyone else sleep with the heat off completely? (homes, heat pump)

[Parsec]

Originally Posted by Bob Lanata

If you bring the temp too cold at night, in order to bring it back up to temp when you want, it may cost you more in the long run. 55 is a good recommendation so it is not that hard on the heating system to bring it back up. I agree with the freezing pipe thing. Some landlords have in the lease to not allow the temp to go below a certain degrees for that reason. I think that 52 is about the lowest. It is also hard on the house with all the expansion and contraction.

Originally Posted by kingeorge

This is great post. Thanks. You spend lot more fuel when constantly starting and stopping, than just cruising.

Yes, the optimal difference between your night and day time temperatures is 7 degrees in terms of cost savings. Any variance over 10 degrees costs you more money to heat in the long run. So if you set it to 65 during the day, then your night time temperature should be 58 or higher depending on how warm you want it.

[SpringMom3]

I've read that its a myth to keep the heat on bc it is more cost effective (or even turn it down less.) here is one such link (but you can find many with the reasoning)
https://campusops.uoregon.edu/utilit...ervation-myths

even if we turned off our heat completely only before bed though, it wouldnt get below 50 in only 8 hrs. maybe next yr when the baby is not a baby anymore i will turn it down more. i did 58 last winter.

[Lincolnian]

I built a passive solar home with a high-efficiency heating system. The furnace doesn't kick on much at all during the day when the sun's out and the house stays about 65. At night I keep it at 62. I burn about 550 to 600 gallons of propane a year. I wouldn't want the house too cold due to mold and as mentioned before it being hard on the house. It's easier to maintain a temperature in a well insulated house than to try and make large temperature movements.

[jayrandom]

Originally Posted by Parsec

Yes, the optimal difference between your night and day time temperatures is 7 degrees in terms of cost savings. Any variance over 10 degrees costs you more money to heat in the long run. So if you set it to 65 during the day, then your night time temperature should be 58 or higher depending on how warm you want it.

This flies in the face of conventional laws of heat transfer. The amount of heat lost is proportional to the temperature difference. Hence it takes more energy to keep something at a larger temperature difference than a smaller one.

Is there some reason that you think 10 degrees is optimal?

[jayrandom]

From the Department of Energy

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. In fact, as soon as your house drops below its normal temperature, it will lose energy to the surrounding environment more slowly. The lower the interior temperature, the slower the heat loss. So the longer your house remains at the lower temperature, the more energy you save, because your house has lost less energy than it would have at the higher temperature. The same concept applies to raising your thermostat setting in the summer -- a higher interior temperature will slow the flow of heat into your house, saving energy on air conditioning. Check out our home heating infographic to learn more about how heating systems and thermostats interact.

Of course if you just turn off your heat overnight (when it's really cold outside) and it doesn't get that cold it means that you're going to save lots of energy because your house is well insulated. That's definitely the best situation to be in.

[Guineas]

I keep my house at 72 overnight. I hate cold houses. Nothing makes me dread getting up early in the morning than a cold house.

If you want lower heating bills, insulate your house and go gas, all this tinkering is a waste of time.

[Parsec]

Originally Posted by jayrandom

This flies in the face of conventional laws of heat transfer. The amount of heat lost is proportional to the temperature difference. Hence it takes more energy to keep something at a larger temperature difference than a smaller one.

Is there some reason that you think 10 degrees is optimal?

No, I didn't pass thermodynamics until my 3rd try in college so I have no opinion of my own. This is what I was told by 2 different heating/HVAC professionals: drop your thermostat by 7-10 degrees at night during the heating season and raise it 7-10 degrees during the cooling season. The links you and springmom provided makes me wonder how valid that claim is though.

[kingeorge]

If you are in stop and go traffic, you will spend more fuel. Period. Thermodynamics theory presented doesn't take in the account different building materials, sun exposure, windows, and levels of insulation. It is not even field, far from it. However just like drivers have different styles, so the people differ at how they approach their heat. Some brake all the time, some cruse, most are in between. We can agree to disagree.

[alg0280]

Stop and go traffic is a bad example. In stop and go traffic you are using energy to accelerate and then you are converting kinetic energy to heat in braking (assuming a traditional, non hybrid car). That would be like instead of turning down the heat and letting the house naturally cool off, instead turning on the A/C to drop the temp 10 degrees, then turn the heat back on to bring it back up.

The reasons to set a floor below which you don't lower the temp is related to comfort, time to heat the house back up, and the potential worry about cold spots that might have pipes freeze. From a purely energy usage scenario the best thing would be to turn off the heat when not home and turn it back on when you were present. For a lot of reasons that is not practical, but the proper temperature to set an away temp to is basically a combination of how quickly your house heats/cools and how long you are going to be away. But leaving it at the same point all the time is definitely not efficient.

[Parsec]

Last night I set the thermostat lower than normal and when I woke up in the middle of the night I felt like my face was frozen. I could not fall back asleep because it was so uncomfortable and now I'm half asleep at work. It doesn't matter how many blankets you use if your face still feels frozen. Not sure how you guys do it!