Thermostat Setback Savings: How Much Do You Save per Degree and Hour?
October 29, 2026
Heat loss from a house depends on the temperature difference between inside and outside. Lowering the thermostat reduces that difference and the energy needed, provided the house is allowed to stay cooler for several hours. A rule of thumb from the US Department of Energy is that you can save about 1% of your heating bill for each degree Fahrenheit you lower the thermostat for 8 hours a day.
On a heating bill of $1,200 a year, a 7-degree setback for 8 hours (for example, from 70°F to 63°F overnight) might save about 7% or $84. A 10-degree setback while at work and asleep (16 hours a day) could save more, up to about 10% to 15% in cold climates.
Skip the math and get your answer instantly:
Open the Percentage Calculator →Savings by Setback
The table uses the 1% per degree per 8 hours rule, scaled proportionally by hours (an approximation): a setback of 3 degrees for 8 hours saves about 3%, or $36 on a $1,200 bill; 7 degrees for 8 hours saves about 7%, or $84; 7 degrees for 16 hours might save up to about 12% to 14%. Savings are larger in mild climates (a bigger share of the difference) and smaller in well-insulated or very leaky homes. Savings aren't doubled by setting the thermostat very low, because the system must run longer or harder to recover.
| Setback | Hours per day | Approximate saving | On a $1,200 bill |
|---|---|---|---|
| 3°F | 8 | 3% | $36 |
| 5°F | 8 | 5% | $60 |
| 7°F | 8 | 7% | $84 |
| 10°F | 8 | 10% | $120 |
| 7°F | 16 | up to about 12-14% | up to about $150-$170 |
Myths About Recovery
A common myth is that reheating the house uses more energy than the savings. In practice, the house loses heat more slowly when cooler, so total energy over the day is lower, even after the recovery. Exceptions are heat pumps with electric backup strips, where large setbacks can trigger inefficient auxiliary heating; use smaller setbacks (2°F to 3°F) or smart thermostats designed for heat pumps. Radiant floor systems respond slowly and benefit less from deep setbacks.
Cooling Works the Same Way
In summer, raising the thermostat when away saves about 1% to 3% for each degree for 8 hours, depending on the climate. Setting it to 78°F when home and higher when away is a common recommendation. Ceiling fans permit a comfortable higher setpoint. Don't set the temperature so high in humid climates that mold can form.
Practical Steps
Program the thermostat to lower the temperature 30 minutes before bedtime and raise it 30 minutes before waking. A programmable or smart thermostat costs $25 to $250 and can pay for itself within a year or two. Seal drafts, improve insulation, and use blankets to make lower temperatures comfortable. Consider health and pets: keep temperatures safe for elderly people, infants, and animals, and protect pipes from freezing.
Frequently Asked Questions
How much does a thermostat setback save?
About 1% of heating costs per degree for 8 hours a day.
Does reheating use more energy than the setback saves?
No, in general the net saving remains positive.
What is the exception?
Heat pumps that rely on electric backup heat during recovery.
Does the rule apply to cooling?
Yes, roughly, when raising the setpoint.
How much does a smart thermostat cost?
Typically $25 to $250.