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.
We costed 12 smart thermostats on what a household keeps after five years: the share of the heating and cooling bill each saves, on this page's default $900 a year, minus what the device costs. Only 1 of 12 holds the position their headline saving suggests. The reason is that the savings barely differ, 8% to 13% across the whole list, while the prices differ more than threefold, $80 to $280. The ecobee Premium saves the most energy at 13% and leaves you $335. An Amazon Smart Thermostat at 10% leaves you $370, and pays for itself in 0.9 years against 2.1.
Method: five years of saving at the maker's claimed share of a $900 heating and cooling bill, minus the purchase price. Counts by band: Under $100 3, $100 to $199 6, $200 and up 3. Two things this cannot tell you: the saving percentages are manufacturer estimates rather than measured, and a bigger bill moves every payback figure down, which is why the page lets you put your own bill in. What it does show is that the gap between the best and worst saver is smaller than the gap between the cheapest and dearest device. Cite this: "usefulHQ Smart Thermostat Payback Study 2026", usefulhq.com/smart-thermostats/.
Reviewed 7 August 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.
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| Thermostat | Price | Typical saving | Saving / yr | Payback | Net after 5 yr | Best for | |
|---|---|---|---|---|---|---|---|
| Amazon Smart ThermostatFastest payback Honeywell-built basics with Alexa control; the fastest way to start saving for the least money. | $80 | 10% | $90 | 11 mo | $370 | Cheapest payback | Check price |
| Wyze Thermostat Very cheap, tidy app, works with most 24V systems; a C-wire adapter is included. | $80 | 10% | $90 | 11 mo | $370 | Budget favourite | Check price |
| Honeywell Home T5 Uses your phone location to adjust when you leave and return; solid Honeywell basics. | $100 | 9% | $81 | 1.2 yr | $305 | Geofencing schedules | Check price |
| Bosch BCC100 Simple colour touchscreen; no learning, but reliable and cheap to buy. | $90 | 8% | $72 | 1.2 yr | $270 | Budget touchscreen | Check price |
| Google Nest Thermostat Mirror finish and auto-eco adjustments; the affordable Nest, without full learning. | $130 | 11% | $99 | 1.3 yr | $365 | Google Home users | Check price |
| Mysa Smart Thermostat One of the few for high-voltage electric baseboard and fan heaters, a common gap. | $140 | 10% | $90 | 1.6 yr | $310 | Electric baseboard heat | Check price |
| Sensi (Emerson) Installs without a C-wire on many systems; no-nonsense app scheduling. | $130 | 9% | $81 | 1.6 yr | $275 | Easiest DIY install | Check price |
| ecobee Enhanced Includes a SmartSensor for occupancy and hot/cold room balancing; strong saver. | $190 | 12% | $108 | 1.8 yr | $350 | Best premium value | Check price |
| Sensi Touch 2 Colour touchscreen and a strong app at a mid-range price. | $170 | 10% | $90 | 1.9 yr | $280 | Touchscreen on a budget | Check price |
| Honeywell Home T9 Room sensors balance temperature across the house; good for larger homes. | $200 | 11% | $99 | 2.0 yr | $295 | Room-by-room comfort | Check price |
| ecobee Premium Air-quality monitor, radar occupancy and built-in Alexa; the most savings on offer here. | $250 | 13% | $117 | 2.1 yr | $335 | Top of the range | Check price |
| Google Nest Learning Learns your routine and adjusts itself; premium build with detailed energy history. | $280 | 12% | $108 | 2.6 yr | $260 | Automatic learning | Check price |
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.