Thermostat Setback Savings Calculator
Estimate what turning your thermostat back while you sleep or are out saves on a year of heating or cooling, using the DOE 1%-per-degree rule.
How it works
Savings % ≈ degrees × (hours ÷ 8) × 1% (capped at 35%) · Savings = bill × savings%
The U.S. Department of Energy estimates you save around 1% on heating or cooling for each degree you set the thermostat back, when that setback is held for an eight-hour stretch such as overnight or the workday. A programmable or smart thermostat automates this so comfort returns before you wake or arrive home. The savings taper off with very deep or very long setbacks — your system has to work harder to recover — so the estimate is capped rather than scaled without limit.
Worked example
On a $1,200 yearly heating and cooling bill, dropping the thermostat 8° overnight for 8 hours saves about 8 × 1% = 8%, or $96 a year. Do it while you are also out for the workday and the longer setback pushes the saving higher.
Frequently asked questions
Does turning the heat down and reheating waste more than it saves?
No. This is a common myth — a building loses heat faster the warmer it is versus outside, so a cooler house during the setback loses less energy overall. The small burst of energy to reheat is far less than what you saved while the temperature was lower.
How is this different from a plain thermostat savings calculator?
This one applies the DOE rule of roughly 1% saved per degree over an 8-hour setback and scales by how long you hold it, giving a percentage saving on your existing heating and cooling spend rather than modeling raw run-time.
What setback is comfortable?
Many households drop 7–10°F overnight in winter and while away, and raise the setting a similar amount in summer. A smart thermostat that pre-heats or pre-cools before you need the room lets you use a deeper setback without noticing it.
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This calculator is for educational purposes. Double-check important results before acting on them.