Most electronic thermostats still use batteries as their main or alternative power source. Thermostats with a separate power supply from your home’s electronic or HVAC systems need batteries. In contrast, thermostats with a shared power supply may add batteries as an alternative power source.
Commonly Used Thermostats and Battery Use:
Thermostat Model | Battery Required | Battery Type |
---|---|---|
Nest Learning Thermostat | Yes | Lithium-ion rechargeable battery |
Honeywell T6 Pro | Yes | 2 AA batteries |
ecobee SmartThermostat | No | N/A |
Johnson Controls TEC3000 | No | N/A |
Find out whether your thermostats need batteries by reading below.
Which Thermostats Use Batteries

Electronic thermostats without a direct connection to the home’s electricity system need batteries.
Batteries are a safe and dependable power source for many electronic devices, making them the prime choice for devices that rely heavily on having a constant power supply. In particular, thermostats must constantly monitor the area’s temperature to provide accurate readings and better temperature control. Batteries help thermostats continue to operate even if emergencies like power outages occur.

Most standalone thermostats use batteries as their main power source.
Standalone thermostats refer to thermostats with a separate power supply from your home’s electronic system or other devices like the AC. These thermostats still regulate and control the room’s temperature through the HVAC system; they don’t share the same power supply. You can think of standalone thermostats like a battery-powered remote that controls your AC and heating.
Thermostats that share a power supply with the HVAC system may or may not need batteries.
This type of thermostat typically comes with your home’s electronic or HVAC systems. These thermostats are connected via a wire to those systems and directly draw electricity from them. Certain models come with a battery compartment that works as an alternative power source in case of any interruptions to the direct power supply.
Most thermostats that use batteries generally require AA or AAA batteries to operate. They also have a digital display and knobs or buttons to control their configuration.
When to Replace Thermostat Batteries
Thermostat batteries should be replaced every eight to twelve months.
Most thermostats use AA or AAA lithium-ion (Li-ion) batteries. These batteries should last for months since thermostats don’t require a lot of power. However, you may need to replace the batteries earlier if you constantly use the thermostat to adjust or check the temperature.
You could wait until your thermostat eventually stops working to replace the batteries, but it’s better to avoid the hassle and change them out in advance.

Most modern thermostats have a digital display or screen showing the temperature reading. Sometimes, those units have a low battery indicator on the screen’s upper or lower corners. This indicates that the batteries are nearly depleted and must be changed.
A malfunctioning thermostat is another sign that battery replacements are in order. A low-battery thermostat doesn’t properly respond to the changes or adjustments- the response may be slow or won’t even take effect. In those cases, changing the battery will resolve the issue.
References
Thermostats – General – BC Campus. https://opentextbc.ca/basichvac/chapter/thermostats/
Video References
One Hour Smart Home
Todd’s Garage
SupplyHouse.com