Why Your Thermostat Changes Its Own Settings in a Heat Wave

You set the thermostat, the heat wave gets worse, and the setpoint is higher again. Before changing the schedule a second time, identify which automatic mechanism is active. A self-changing setpoint usually comes from one of four places: Nest Seasonal Savings, ecobee eco+ Community Energy Savings, a utility demand-response event, or Home/Away presence sensing.

Use the visible signal as your starting point:

• A yellow gear-with-leaf icon on a Nest points to Seasonal Savings.
• An ecobee app banner or event notice points to eco+ Community Energy Savings.
• A utility text, email, or demand-response event notice points to a grid program.
• The word “Eco,” especially alongside an away or occupancy state, points toward presence-based Eco, although Eco by itself does not prove which trigger is responsible.

Check Nest Seasonal Savings First

Nest Seasonal Savings makes small changes to the temperature schedule rather than behaving like a single permanent override. During a campaign, the adjustments can total roughly 2°F, with changes concentrated around periods when the home is asleep or unoccupied. The Nest thermostat displays a yellow gear-with-leaf icon while the program is active. [1]

The icon matters because a gradual schedule change can look like a thermostat malfunction. If the yellow gear-with-leaf symbol is present, open the Nest app and go to History, then choose Stop. In the Google Home app, use Settings, Temperature preferences, Seasonal savings, and Leave Seasonal Savings. These are support-page-documented and source-verified paths as of August 25, 2026; they are not a personally reproduced fix. [1]

There is a consequence worth noticing before you select the opt-out: once you leave Seasonal Savings, you cannot rejoin until the next season in which the program is available. Availability is also limited by region and setup, including the United States and Canada except Quebec for English-US setups. [1]

If you are looking for the setting and keep getting sent back to the schedule, that is not unusual. The disable control can be difficult to locate, and how-to documentation notes that it is possible to re-enable the program accidentally. [2]

Do Not Confuse Seasonal Savings With Eco

A Nest displaying Eco does not, by itself, identify Seasonal Savings. Eco Temperatures are a separate temperature range that can activate when Nest presence sensing decides nobody is home. For cooling, the available Eco range is 76°F to 90°F. When the device's own sensors are being used, the change into Eco can take up to two hours after the home is judged unoccupied, and the thermostat can switch back when someone returns. [4]

Model behavior is important here. On a third-generation Nest Learning Thermostat or Nest Thermostat E, Eco can remain active until it is switched back manually. The newer Nest Thermostat can leave Eco at the next scheduled change and can hold Eco for up to 24 hours. [4]

Check the thermostat's presence and Home/Away settings, then look for an away state or an active Eco temperature. Stop the presence-based change through the relevant Home/Away or presence-sensing controls, or switch the thermostat out of Eco according to the behavior of your model. Turning off Seasonal Savings does not turn off this mechanism. The two controls have different causes and different effects.

Look for an ecobee Energy Event

On ecobee, eco+ Community Energy Savings is an event-based program. It may precool the home before peak hours and then adjust the thermostat slightly during the event. The ecobee app can show a banner or event notice, so check the app before editing the comfort schedule. [3]

If the notice identifies Community Energy Savings, open the ecobee app's eco+ energy preferences and use the Community Energy Savings opt-out control. The exact offer and controls can depend on the energy provider. ecobee reports that providers have paid more than $25 million through the program and that rewards can reach $125, but those figures are vendor- or provider-reported rather than independent measurements. [3]

Check the Utility Before Blaming the Thermostat

A utility demand-response event can look almost identical to a thermostat feature because the result is the same: the device receives permission to adjust the setpoint during a period of high demand. During heat-wave alerts, Flex Alert guidance asks consumers to set thermostats to 78°F or higher. Utilities also operate voluntary programs that briefly adjust participating smart thermostats in exchange for incentives. [5]

Search your email, text messages, utility account, and thermostat app for an event notice. Look for terms such as demand response, energy event, peak event, Flex Alert, conservation event, or a named utility program. A utility's notice is stronger evidence than the word Eco on the thermostat, because Eco can come from presence sensing instead.

To stop future changes, use the opt-out or participation control in the utility account or the smart-thermostat enrollment screen. If the event is already underway, follow the notice's stop or override instructions. A utility demand-response opt-out does not disable Nest Seasonal Savings, ecobee eco+, or Home/Away presence sensing. Utility guidance also commonly treats these events as temporary conservation measures, not as a replacement for the temperature schedule you chose. [5][6]

Return to a Deliberate Heat-Wave Schedule

Once the active mechanism is stopped, set the schedule again and watch whether it changes after the next expected event or occupancy transition. ENERGY STAR's commonly cited summer reference is 78°F when home, about 85°F when away, and about 82°F while asleep. Those numbers are a starting point rather than a mandate; comfort, health, humidity, pets, and the home's actual cooling capacity still matter. [7]

For a ready-to-enter baseline, use the site's Nest and ecobee heat-wave settings or its broader heat-wave thermostat settings recipe. Those schedules become useful after the cause of the change is known; entering them repeatedly while an automation remains active only creates another setting for the thermostat to override.

The thermostat probably is not broken. The important distinction is that “opt out” is not one universal switch: leaving Nest Seasonal Savings does not stop a utility event, ending a demand-response enrollment does not stop presence-based Eco, and seeing Eco does not tell you which trigger moved the temperature. Identify the signal, stop that specific mechanism, and then restore the schedule you actually intend to use.

References

1. Seasonal Savings — Google Home Help
2. How to Disable Nest Seasonal Savings — Service Experts
3. eco+ — ecobee
4. Eco Temperatures — Google Home and Nest Help
5. Save Energy — Flex Alert
6. Duke Energy Offers Tips to Save Energy and Money as Wide-Spread Heat Wave Brings Triple-Digit Temperatures to the Carolinas — Duke Energy
7. What should your thermostat be set at during summer? — The Hill