Smart Thermostats: How Much Do You Really Save?
Real-world utility data on smart thermostat savings, plus the homes where the math just doesn't work.
Smart thermostat manufacturers advertise 20-30% savings on heating and cooling bills. Real-world utility data shows 8-15% is more typical — still a respectable payback on a $150-$280 device, but not the windfall the marketing implies.
Where savings actually come from
The savings aren't from the algorithm — they're from the setbacks. A smart thermostat reliably setbacks temperature when no one's home and at night, where a manual thermostat usually doesn't get adjusted. Households that already run aggressive manual setbacks see minimal additional savings.
Geofencing (using your phone's location to detect when the house is empty) is the single highest-impact feature. Schedule-only smart thermostats save much less than geofencing-enabled ones.
When it doesn't pay back
Heat pump homes: setbacks can actually increase energy use because heat pumps run inefficiently at high recovery rates. Use a heat-pump-specific thermostat (ecobee, Sensi) and program small setbacks only.
Homes occupied 24/7 (work-from-home, retirees): the setback window shrinks dramatically. Payback can stretch past 5 years.