Does Turning the Thermostat Down at Night Actually Save Money?
Updated August 2026
In plain numbers: Yes. A cooler house loses heat more slowly, so every hour it spends below your normal setting burns less fuel, and the morning reheat never costs as much as the night saved. The working rule is about 1% off the heating bill per degree of setback held for 8 hours, which means a 7 to 10°F setback over night and workday usually trims around 10%. The one real exception is a standard heat pump, where a deep morning recovery can wake up the resistance backup strips and eat the savings. On those, keep setbacks shallow or use a thermostat that knows it's driving a heat pump.
Why the reheat myth won't die
You've heard it from a relative, possibly at Thanksgiving: the furnace has to work so hard to warm the house back up that you save nothing. It sounds right. It isn't.
Your house leaks heat in proportion to the gap between the air inside and the air outside. Hold 70°F on a 30°F night and you're fighting a 40-degree gap for eight hours. Let the house drift to 62°F and the gap shrinks to 32, so less heat walks out through the walls and attic every single hour. In the morning the furnace has to put back what was lost overnight, but that amount is smaller than what it would have spent holding 70 all night. The reheat is real. It's just always cheaper than the alternative.
The Department of Energy's long-standing number still holds up: roughly 1% saved per degree of setback per 8 hours. Stack an 8°F setback across 16 hours a day, night plus an empty workday, and 10 to 15% comes off the heating bill. It costs nothing and keeps paying every winter.
Put your own bill through it
Say your January gas bill runs $210 with the house held at 70°F around the clock. Drop to 62°F from 10:30 p.m. to 6:00 a.m. and again from 8:30 a.m. to 5:00 p.m. while everyone's out. That's 8 degrees for 16 hours, which the rule of thumb puts near 16%, and real houses usually land a bit under the rule because recovery eats into the edges. Call it 11 to 14%, or $23 to $29 that month. Over a five-month season on a bill like that, you're looking at $100 or more for pressing a few buttons in October.
Now look at the other lever, the number you set when you're home. Each degree of standing temperature is worth about 3% of the seasonal bill. Going from 70°F to 68°F while you're awake is worth roughly 6% on its own, and in a lot of households that's an easier negotiation than getting anyone to accept a cold bedroom.
The heat-pump exception
Standard air-source heat pumps change the story. Ask one for a big jump at 6 a.m. and many systems call in their electric resistance strips to close the gap fast. Those strips deliver heat at about three times what the compressor charges for it, so a deep setback recovered on strip heat can genuinely cost more than leaving the temperature alone.
The fixes are well known. Keep heat-pump setbacks shallow, 2 to 4°F. Use a thermostat with heat-pump logic that starts recovery early and does it with the compressor only; most smart thermostats handle this once they're configured for a heat pump, and many call the setting adaptive or smart recovery. Dual-fuel systems and modulating inverter units mostly don't have the problem.
The schedule only works if it runs
Every number above assumes the setback actually happens, every day, without anyone thinking about it. That is the whole value of a programmable or smart thermostat. A basic $30 programmable running a boring schedule beats a $250 smart unit that somebody switched to 'hold' in November and forgot.
Reasonable defaults if you want a starting point: 68°F while you're home and awake, 60 to 65°F while you sleep or the house is empty. Go lower if sweaters are welcome. Keep the unoccupied setting at 55°F or above in cold snaps so the plumbing in exterior walls stays out of trouble.
FAQ
How much does lowering the thermostat save?+
About 1% per degree per 8 hours of setback. A 7 to 10°F setback over night and during the workday typically trims around 10% off the heating bill. Each degree you lower the everyday setting is worth roughly 3% over the season.
Is it cheaper to keep the house at one temperature?+
Not with a furnace or boiler. A cooler house leaks less heat, so setbacks always save fuel even after the morning reheat. The exception is a standard heat pump, where a deep setback can trigger expensive backup strips; keep those setbacks to 2 to 4°F or use heat-pump-aware recovery.
What temperature should I set my thermostat in winter?+
A common starting point is 68°F when you're home and awake and 60 to 65°F when you're asleep or away. Every degree lower saves about 3% on heating over the season, so pick the lowest setting your household will actually live with.
Do smart thermostats save more than programmable ones?+
Only when the programmable one isn't being used. The savings come from the setback, not the Wi-Fi. A $30 programmable that runs its schedule every day saves about the same as a smart unit; the smart one earns its price with heat-pump recovery logic and by stopping people from overriding the schedule.