How much does a smart thermostat actually save?
Short answer: ENERGY STAR says the average home with a certified smart thermostat saves 8% on heating and cooling costs, or $50 per year. Actual savings depend on your bill, climate and habits. On an assumed $1,200 yearly heating and cooling bill, 8% is about $96 a year. Homes already using setbacks will save less.
What ENERGY STAR says a smart thermostat saves
ENERGY STAR’s technical bulletin states that with a certified smart thermostat, “the average home saves 8% on heating and cooling costs, or $50 per year.” ENERGY STAR says certified models are independently certified to deliver savings based on actual field data.
Two things to keep in mind:
- It is an average. Some homes save more, some save almost nothing.
- It is a share of heating and cooling only. It does not apply to your whole electric or gas bill.
ENERGY STAR also notes that almost half of a home’s annual energy bill goes to heating and cooling, which it puts at more than $900 a year.
How much will a smart thermostat save me?
The formula is simple:
Yearly savings = yearly heating and cooling cost × savings rate
The table uses ENERGY STAR’s 8% average. The bill amounts are assumptions; use your own.
| Assumed yearly heating and cooling cost | Savings at 8% | Payback on an assumed $150 thermostat |
|---|---|---|
| $600 | $48 | 3.1 years |
| $900 | $72 | 2.1 years |
| $1,200 | $96 | 1.6 years |
| $1,800 | $144 | 1.0 year |
Worked example. Assume your home spends $1,200 a year on heating and cooling. At 8%, that is $1,200 × 0.08 = $96 a year. If the thermostat costs $150 installed, payback is $150 ÷ $96 = about 1.6 years. The $150 price is an assumption for the math, not a quote.
To estimate your heating and cooling cost, compare a mild spring or fall month with a peak winter or summer month on your utility bills. The difference over the year is a rough guide.
Where the savings come from
A smart thermostat does not make your furnace or air conditioner more efficient. It saves by running the system less, mostly through setbacks while you sleep or are away.
The U.S. Department of Energy says turning your thermostat back 7 to 10°F for 8 hours a day can save up to 10% a year on heating and cooling. A basic programmable thermostat can do this too, if you actually program it. The case for a smart model is that it does it without you having to remember.
That also explains who saves the least. If you already set the temperature back every night and every workday, a smart thermostat has little left to add.
What do Nest and ecobee claim?
Manufacturers publish their own figures. Treat these as maker claims, not independent results.
- ecobee says its customers in North America “saved up to 26%” on heating and cooling costs. Per its fine print, that comes from an internal analysis in April 2021, measured against a 72°F baseline. “Up to” is a maximum, not a typical result.
- Google Nest also publishes savings claims. We could not verify a current figure on an official Google page, so we leave it out.
The ENERGY STAR 8% average is the more conservative number to plan with.
Do smart thermostats work with heat pumps?
Many do, but be careful with large setbacks. On some heat pump systems, a big temperature recovery in the morning can bring on electric backup heat. That backup heat costs much more to run than the heat pump itself, which can eat into the savings.
Results vary by thermostat and equipment. Check the thermostat’s heat pump settings or ask your installer. See our guide on heat pumps in cold weather for how auxiliary heat works.
ENERGY STAR also advises making sure any smart thermostat is compatible with your heating and cooling system. For the very highest efficiency equipment, it says you may want a controller from the same company.
Will a smart thermostat work with my wiring?
Check before you buy. Many smart thermostats need a constant power source, often supplied by a common wire, called a C-wire. Some older systems do not have one. Each maker publishes a compatibility checker; use it with a photo of your current wiring.
Safety: turn off power to the heating and cooling system at the breaker before removing an old thermostat. If you see thick wires labeled 120 V or 240 V, as with some electric baseboard heaters, stop. Those are line-voltage systems and need a compatible thermostat. Hire an electrician if you are unsure.
Quick answers
Do smart thermostats really save money? On average, yes. ENERGY STAR says the average home with a certified model saves 8% on heating and cooling costs, or $50 per year. Your dollar figure depends on your bill.
How long does a smart thermostat take to pay for itself? It depends on your bill and the price. On an assumed $1,200 yearly heating and cooling bill, 8% savings pays back an assumed $150 thermostat in about 1.6 years.
Is a smart thermostat better than a programmable one? Both save energy through setbacks. A smart model mostly helps people who would not program, or keep programming, a basic thermostat.
Is ecobee’s 26% savings claim realistic? It is a maker’s “up to” figure from an internal analysis against a 72°F baseline. ENERGY STAR’s 8% average is the safer planning number.
Should I use big setbacks with a heat pump? Be cautious. A large morning recovery can trigger costly backup heat on some systems, so check the thermostat’s heat pump settings.