Winter thermostat: start at 68°F, then set it back 7 to 10 degrees while you sleep or are out

Where to start: about 68°F

DOE’s winter advice is to set the thermostat as low as is comfortable while you’re home, and it suggests starting around 68 to 70°F and adjusting from there. That makes 68°F a starting point, not a rule. If the house feels fine at 67, that’s fine too. [S2]

Heating and cooling are a big share of a home’s energy use. DOE puts them together at about 32% of the energy a typical home uses, the largest single slice. [S1]

The setback: 7 to 10 degrees, about 8 hours

The savings come from turning the heat down when nobody needs it. DOE says turning the thermostat back 7 to 10°F for 8 hours a day in fall and winter can save as much as 10% a year on heating and cooling. Its 2024 bulletin says the same about setting back while you’re away. [S1] [S2]

• Pick your 8 hours. Overnight while you sleep, or the workday while the house is empty. The Building America Solution Center and ENERGY STAR both describe setbacks for when people are asleep or away. [S3] [S5]
• Let the thermostat do it. DOE says a programmable thermostat can bring the house back up before you get home, if you set it to match your routine. [S2]
• Expect more in milder places. The Building America Solution Center says the percentage saved is greater in mild climates than in severe ones. [S3]
• “As much as” is a ceiling. DOE’s 10% is an upper figure for heating and cooling together, not a promise for every home. [S1] [S2]

Setback check

Enter the temperature you keep while you’re home and awake to see DOE’s setback range, checked against the 55°F floor and WHO’s 18°C guideline.

The math is simple: subtract 7 and 10. From 68°F that gives 58 to 61°F. WHO’s guideline is 18°C, which is 64.4°F, so a full DOE setback from 68 dips below it. That matters most for the people WHO says may need it warmer. [S1] [S2] [S7]

Heat pumps are the exception

DOE says not to do the 7 to 10 degree setback with a heat pump unless you have a smart or programmable thermostat designed for heat pumps. DOE’s heat pump tips explain why: don’t set back a heat pump manually if that makes the backup electric-resistance heat come on, because that kind of heat is more expensive. [S1]

• Look for adaptive recovery. The Building America Solution Center says a heat pump thermostat should have adaptive recovery, which starts warming earlier and more gradually so the heat pump can do the work without much auxiliary heat. It says these thermostats learn the house within about a week. [S3]
• Keep changes small. CEE’s heat pump guide says heat pumps are efficient with a steady setting. It says to avoid abrupt changes of 3°F or more and to adjust a few degrees at a time in the evening and morning. [S4]
• Save big setbacks for trips. CEE says setbacks typically save energy with a heat pump when you’ll be gone more than a day, and that turning it off while you’re out can make it run inefficiently when it restarts. [S4]
• Watch the aux light. CEE calls auxiliary heat costly and inefficient. If the thermostat shows it constantly, call a qualified HVAC technician. [S4]

When to skip or shrink the setback

Hard-freeze nights. The Red Cross says to keep the thermostat at the same temperature day and night during cold snaps to prevent frozen pipes. The heating bill may go up a little, but a burst pipe costs far more. Our frozen pipes guide covers the rest. [S6]

Away in cold weather. Leave the heat on, set no lower than 55°F, the Red Cross says. [S6]

Someone vulnerable at home. WHO’s housing guideline proposes 18°C (64.4°F) as a safe indoor temperature for the general population during cold seasons. It says older people, children and people with chronic illness, especially heart or lung disease, may need a higher minimum. [S7]

Programmable or smart

Either one can run a setback for you. DOE says a programmable thermostat stores several daily settings that you can override without changing the rest of the program. It has to be set up, and DOE says it’s cheaper than a smart model. A smart thermostat is a Wi-Fi model that can learn the temperatures you like, build its own schedule and let you adjust it from your phone. [S1]

ENERGY STAR says certified smart thermostats are independently certified, based on actual field data, to deliver energy savings. Some use geofencing to tell when you’re on the way home and adjust the temperature. Before buying, ENERGY STAR says to make sure the thermostat works with your heating and cooling system, and to keep a Wi-Fi model reasonably close to the router. Certified models are also designed to work with programs some utilities offer, which can come with incentives. [S1] [S5]

Help the heat along

• Clear the registers. DOE says to keep registers, baseboard heaters and radiators clean and not blocked by furniture, carpet or drapes. [S1]
• Use the sun. Open curtains on south-facing windows during the day and close them at night. [S1]
• Reverse the ceiling fan. DOE says to run it clockwise in winter to push warm air down from the ceiling. [S1]
• Check the filter. Our furnace filter guide covers size, MERV and when to change it. [S1]
• Heat pump fan. CEE says to start with the Auto fan setting, since running the indoor fan nonstop can hurt heat pump performance. [S4]

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