Smart Thermostat Savings Calculator
Compare explicit heating and cooling savings with installation cost and annual fees.
A QUICK WALKTHROUGH
How to use this tool
- Enter separate period costs and your own savings scenarios.
- Calculate and review every row.
- Copy the report or download TXT.
Formula and units
Period saving = heating × heating%/100 + cooling × cooling%/100. Annual values = period values × periods/year. Net saving = annual gross saving − annual fee. Simple break-even = upfront cost ÷ positive annual net saving.
Scope and assumptions
No default saving fraction or tariff. Optional blank installation and annual fee mean zero. A period is a user-defined billing interval; periods/year is explicit. Fees exclude the one-time installation. Break-even ignores discounting and changing prices. DOE thermostat guidance describes conditional savings, not a universal rate: https://www.energy.gov/energysaver/thermostats
Local processing
Inputs remain in this browser. Copy and TXT use the same fixed full precision report.
GOOD TO KNOW
Common questions
What does this result mean?
It is arithmetic from your measurements and explicit assumptions, not a prediction of real performance.