Smart Thermostat Savings Calculator
Estimate what a smart thermostat saves on heating and cooling from your energy bill, and how quickly the device pays for itself.
How it works
Annual saving = heating cost × heating save% + cooling cost × cooling save% · Net cost = device − rebate · Payback = net cost ÷ annual saving
A smart thermostat saves by automatically setting back the temperature when you’re asleep or away, so the savings scale with what you already spend on heating and cooling. Manufacturers cite figures around 8–15%, with heating usually saving a larger percentage than cooling. Applying those rates to your actual bills — not a national average — gives a realistic annual saving, and dividing the device cost by it shows how fast a roughly $200 thermostat earns its keep.
Worked example
On a $900 heating bill saving 12% and a $500 cooling bill saving 8%, the yearly saving is 108 + 40 = $148. A $220 thermostat with a $50 rebate nets $170, paying back in about 1.1 years and saving roughly $570 over five years.
Frequently asked questions
How much does a smart thermostat really save?
Independent estimates cluster around 8–15% of heating and cooling costs, with the biggest gains for homes that previously never set back the temperature. If you already turn the heat down manually at night, your incremental savings will be smaller.
Does a smart thermostat save on cooling too?
Yes, but usually a smaller percentage than heating, because cooling setbacks are limited by comfort and humidity. This calculator lets you set separate heating and cooling savings rates to reflect that.
Are there rebates for smart thermostats?
Many electric and gas utilities offer $50–$100 rebates, and some give a free unit for enrolling in a demand-response program. Subtracting the rebate here shortens the payback considerably.
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This calculator is for educational purposes. Double-check important results before acting on them.