Do Smart Thermostats Save Money? What the Data Shows

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The box says “save up to 26%.” Your neighbor swears hers paid for itself in one winter. Your brother-in-law says it’s a gadget that does nothing a $30 thermostat can’t. Before you spend $100 to $280 on a smart thermostat, it’s fair to ask who’s right.

Yes, smart thermostats save money in most homes, but less than the box suggests. ENERGY STAR puts the average at about 8% of heating and cooling bills, or about $50 a year, for certified models. Makers quote 12% to 26%, measured against their own baselines. You’ll save the most if your home sits empty for long stretches and you didn’t already turn the heat down at night.

The numbers at a glance

Source	What it says	What kind of number
ENERGY STAR (EPA)	About 8% of heating and cooling bills, about $50 a year, on average	Program average for certified smart thermostats
ENERGY STAR criteria	Certified models must cut heating run time at least 8% and cooling run time at least 10% (national averages, field data)	Minimum to earn the label
Cadmus for Vectren (Indiana utility)	Nest homes cut heating gas use about 12.5%; programmable thermostat homes about 5.0%	Independent utility evaluation, 2013–2014
Florida Solar Energy Center	Heating and cooling savings averaged 9.5% in Florida homes after installing smart thermostats	Independent field study, about two dozen homes
Google (Nest)	About 12% on heating and 15% on cooling bills	Maker claim
Sensi (Copeland)	About 23% on HVAC energy costs	Maker claim
ecobee	Up to 26% on heating and cooling costs, compared with holding 72°F	Maker claim (“up to”)

How a smart thermostat saves money

A smart thermostat doesn’t make your furnace or air conditioner more efficient. It saves by running them less: letting the house drift cooler in winter and warmer in summer while you’re asleep or away. ENERGY STAR describes the tools it uses: learning your preferences, geofencing (your phone tells it when you’ve left), and remote control so you can fix a forgotten setting from anywhere.

The physics is on your side. The U.S. Department of Energy explains that a cooler house loses heat to the outdoors more slowly, so the furnace does not “work harder” to catch up after a setback. DOE says you can save as much as 10% a year on heating and cooling by turning your thermostat back 7 to 10°F for 8 hours a day, and that savings from setbacks are larger in milder climates.

What a smart thermostat adds is follow-through. With an ordinary programmable thermostat, a Lawrence Berkeley National Laboratory study found almost 90% of people rarely or never set a weekday or weekend program, and about half left the thermostat on hold. A smart thermostat puts the setback back in place on its own when it sees the house is empty.

What ENERGY STAR requires

ENERGY STAR’s smart thermostat label is the most useful independent check, because it’s based on what happens in real homes, not in a lab. Each maker analyzes a year of data from hundreds of customers’ homes with EPA software, comparing how long the heating and cooling ran against a baseline. To qualify, under the specification ENERGY STAR lists as current in October 2026, a product family must show:

• Heating: at least an 8% cut in annual heating run time (weighted national average, at the lower 95% confidence limit), and at least 4% for the 20th percentile of homes.
• Cooling: at least a 10% cut in annual cooling run time, and at least 5% at the 20th percentile.
• Basic function without the internet: it must keep working as a thermostat if it loses its connection.
• Feedback and control: a schedule, information on your heating and cooling run time, and feedback on how your settings affect energy use.
• Low standby power: 3.0 watts or less on average while connected, and accuracy within ±2.0°F.
• Utility programs: the ability to work with utility programs that ease demand on the grid at peak times.

For heat pumps, ENERGY STAR only requires makers to report how much electric backup heat their homes use; there’s no pass mark. It also notes that homes with variable-capacity heat pumps generally do best with the thermostat the equipment maker recommends, certified or not. A newer Version 2.0 specification has been in development; check the ENERGY STAR page for the current rules.

How to read the makers’ savings claims

Makers’ numbers are real analyses of their own customers, but they’re built to look good. Three things to check:

• The baseline. ecobee’s “up to 26%” (from its own April 2021 analysis) compares eco+ users with a home held at 72°F all day and night. If you already turn the heat down at night, your starting point is lower and so are your savings.
• “Up to.” An “up to” number describes the best cases, not the typical home.
• Who was measured. Sensi’s “about 23%” compares Sensi users who adjusted their temperature by about 4° on average with users who made no adjustments. Google’s 12% heating and 15% cooling figures come from its review of customers’ energy bills. People who buy a smart thermostat and use its features are not a random sample.

Independent studies land closer to the middle. The Florida Solar Energy Center measured a year of sub-metered data in Florida homes (28 smart thermostats installed) before and after a smart thermostat went in, and found heating and cooling savings averaged 9.5%, with a wide spread: some homes saved a lot, a few used more. In Indiana, Cadmus found Nest homes saved about 12.5% of heating gas. ENERGY STAR’s 8% sits a little below both.

When a smart thermostat saves less

• Someone is always home. ENERGY STAR says homes that are always occupied will see less savings. The Cadmus evaluators found the same for households where people were home on weekdays.
• You already set back the temperature. If you turn the heat down every night by hand, much of the saving is already yours.
• A heat pump with the wrong setup. DOE warns that big setbacks on a heat pump can switch on its electric backup heat during recovery, canceling the savings. Pick a thermostat that manages auxiliary heat, and keep setbacks modest. See the best smart thermostat for a heat pump.
• You override it. Turning the heat to 75°F every time you feel a chill undoes the work. Give the schedule a few weeks.
• No Wi-Fi. Without a connection, geofencing and remote control don’t work, and you’re left with a programmable thermostat.

How long until it pays for itself?

ENERGY STAR says almost half the average household’s energy bill goes to heating and cooling, more than $900 a year. Using its average saving of about $50 a year, here’s our rough payback estimate (price ÷ yearly savings), before any rebate:

Thermostat price	Saves $50/yr (ENERGY STAR average)	Saves $100/yr (bigger home or harsher climate)
$80	About 1.6 years	About 10 months
$110	About 2.2 years	About 1.1 years
$165	About 3.3 years	About 1.7 years
$280	About 5.6 years	About 2.8 years

Estimates only. Your savings depend on your climate, your system, your energy prices and your habits. Two things shorten the payback: rebates (many utilities discount ENERGY STAR smart thermostats; see smart thermostat rebates) and peak-time programs, where some utilities pay you to let them raise your AC setting a few degrees on the hottest afternoons. There is no federal tax credit for smart thermostats in 2026, so check your state and utility.

ENERGY STAR certified thermostats to consider

Prices change often. The prices below are what we saw at the maker or a major retailer in October 2026; check the current price before you buy. All four are listed as ENERGY STAR certified and need no subscription.

The ecobee Enhanced uses a built-in radar sensor to tell when you’re home, and its eco+ features are free; ecobee lists it at $164.99 on sale. The Amazon Smart Thermostat has the shortest payback at about $80 list, if you have a C-wire. Compare every option in the best smart thermostats of 2026.

Check the ecobee Enhanced price on Amazon

Get the most out of a smart thermostat

• Turn on the away features (geofencing for everyone in the house, or the occupancy sensor).
• Use a real nighttime setback; see the best thermostat settings for winter and summer.
• Read the monthly report: rising run time on a mild month can flag a dirty filter or an HVAC problem.
• Join your utility’s peak-time program if it pays.
• Install it right: on 24-volt systems, turn off power at the breaker first; electric baseboard heat is line voltage and needs a licensed electrician.

Keep exploring: our smart thermostats guide, smart vs programmable thermostats, smart thermostats with no subscription and ecobee vs Nest. For more ways to cut your bill, see how to lower your electric bill, heat pumps and thermal energy, or browse Smart Thermostats.

Smart thermostat savings questions

How much does a smart thermostat save per year?

ENERGY STAR says certified smart thermostats save about 8% of heating and cooling bills on average, roughly $50 a year, and possibly more depending on your climate, comfort settings, how often the home is empty and your equipment. Makers claim 12% to 26%, but those figures use their own baselines.

Is a smart thermostat worth it if I work from home?

Less so. ENERGY STAR notes that homes that are always occupied see smaller savings, because there’s little “away” time to save on. You can still save with a nighttime setback, by heating or cooling only the rooms you use, and through utility peak-time programs. A cheaper model, or one your utility discounts, makes the math easier.

Does turning the heat down at night really save energy?

Yes. The DOE explains that a cooler house loses heat more slowly, so the furnace doesn’t use more energy catching up than it saved. DOE says turning the thermostat back 7 to 10°F for 8 hours a day can save as much as 10% a year. Heat pumps are the exception to handle carefully: use small setbacks and smart recovery.

Are the savings claims on the box true?

They come from real data, but read the fine print. ecobee’s 26% is “up to” and compared with holding 72°F all day; Sensi’s 23% compares users who adjusted their temperature with users who didn’t. Independent studies have found about 9.5% (Florida) and 12.5% of heating gas (Indiana), and ENERGY STAR’s average is 8%.

Can I get a tax credit for a smart thermostat in 2026?

No federal one: the home efficiency credit (25C) ended for work completed after December 31, 2025. Many utilities still offer rebates on ENERGY STAR smart thermostats, so check your utility’s website or the ENERGY STAR Rebate Finder.