Smart thermostats with the ENERGY STAR: what certification requires, and what the savings figures mean

A smart thermostat that carries the ENERGY STAR has been certified on how it performed in real homes, not only in a lab. Under the Environmental Protection Agency's criteria, certified models must cut heating system run time by at least 8% and cooling run time by at least 10%, measured on a year of data from hundreds of customers' homes, and must meet limits on temperature accuracy and standby power. When we read EPA's list of certified products on November 14, 2026, it had 121 entries from 24 partner companies, by our count.

ENERGY STAR says heating and cooling make up almost half of the average American household's annual energy bill, more than $900 a year. Its criteria set out what a thermostat must do to carry the label.

What the label requires

EPA's key product criteria say certified smart thermostats must:

• work as a basic thermostat when the connection to the service provider is lost
• give residents some feedback on the energy consequences of their settings
• provide information on heating and cooling energy use, such as monthly run time
• let users set a schedule
• work with utility programs to prevent brownouts and blackouts, while keeping the user's ability to override those requests

The device itself must hold a static temperature accuracy of ±2.0°F or better, use no more than 3.0 W on average in network standby, and enter standby within 5.0 minutes of the last interaction. ENERGY STAR says certified products are independently certified based on actual field data.

What the savings figures mean

To show a model meets the savings criteria, its service provider runs EPA's software over a year of real-world use in hundreds of its customers' homes and works out national heating and cooling figures from the results.

EPA explains that the lower 95% confidence limit is similar to an average but allows for the chance that the sampled homes all happened to be higher savers, and that the 20th percentile means four out of five homes in the sample saved at least that much. The figures are cuts in how long heating and cooling equipment runs; in our reading they are not a promise of a set cut in any one household's bill, which also depends on its equipment, climate and settings.

What EPA's certified list shows

We downloaded EPA's dataset of certified smart thermostats on November 14, 2026. It listed 121 products. The table shows the partner companies with the most entries; an entry is a certified product listing, not a measure of sales or quality.

By our count, 103 entries list Wi-Fi among their communication methods, 35 Bluetooth, 10 Z-Wave and 8 Zigbee; many list more than one. Network standby figures ranged from 0.04 W to 2.59 W, with a median of 0.51 W. Of the 121 entries, 106 are listed for the United States and Canada, 14 for the United States only and one for Canada only. Sixteen were certified in 2026, the latest on November 10.

ENERGY STAR's buying guidance asks shoppers to make sure a smart thermostat is compatible with their heating and cooling system, and says owners of the highest-efficiency equipment, such as air conditioners rated at 20 SEER or higher, may want a controller from the same company. It also notes that a Wi-Fi model kept too far from the router can disconnect. Its partners sponsor rebates on some certified products, which the site's rebate finder lists by ZIP code.

What may change

The current Version 1.0 specification took effect on January 1, 2017. EPA lists a Version 2 specification as in development. The newest entries on its development page date from late 2024: Draft 2, released on November 21, 2024, a second draft of the method for demonstrating field savings, with comments due by December 20, and a webinar on December 4. In its cover letter, EPA said the updated method would cover a wider variety of installations, allow line-voltage thermostats that control electric baseboard heating, and give more stable savings results.

EPA also wrote that a 1 W standby limit proposed earlier was too restrictive and that it intended to propose 1.5 W in the next specification draft. By our count, 26 of the 121 certified entries list average network standby above 1.5 W. The development page listed no later draft when we read it on November 14, 2026.

Compatibility and software support matter as much as the label. Our guides to Matter smart home devices and to older Nest thermostats' end of app support cover those questions.