They all save roughly the same slice of your heating and cooling bill, so the winner is usually the cheapest one that fits your system. Put in your yearly HVAC spend and this works out how long each thermostat takes to pay for itself, and what you are left with after five years.
Reviewed 11 July 2026. Prices in USD. Savings are estimates based on ENERGY STAR and manufacturer figures of roughly 8 to 13 percent of heating and cooling cost; your real saving depends on your home, climate and habits.
Roughly half of a typical home energy bill. Change it and every payback time updates.
| Thermostat | Price | Typical saving | Saving / yr | Payback | Net after 5 yr | Best for |
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Modestly, yes, about 8 to 12 percent of heating and cooling cost per ENERGY STAR, so roughly $70 to $110 a year on a $900 bill. Savings are similar between models, so the cheapest capable one usually pays back fastest.
Usually the cheapest that fits your system, like the Amazon Smart Thermostat or Wyze around $80, which can break even in under a year. Premium models save a touch more but cost more, so they take longer. Enter your bill to see your own numbers.
Many do, for constant power, though some Nest, Sensi and ecobee models work without one or include an adapter. Check your wiring first; a model that runs without a C-wire avoids an electrician visit.
The extra money buys features, room sensors, learning, air-quality monitoring, nicer screens, not usually much more saving. Worth it for comfort and convenience, but not on payback alone.