Lennox thermostats are quite popular. Do you know what powers your Lennox thermostat? Getting to know the power source of your thermostat can help you get it working. Thermostats can either be powered by batteries or mains electricity. Others contain the battery as a power backup option.  

Not all Lennox thermostats have batteries. This is dependent on the model and whether batteries are required for it to function properly. Most of them are connected to the building’s main power supply, but some need batteries to operate probably. You can check the model’s product description to know its power source.

Keep on reading to learn how to know Lennox thermostats that use batteries and how to change batteries when they become obsolete. You will also know where the batteries are located in these thermostats.

Do All Lennox Thermostats Have Batteries?

Batteries store chemical energy, which is converted to electricity whenever it is required. This occurs through a chemical reaction whenever a battery is connected to the external circuit. In this case, the ions move from the electrolyte between the negative and positive sides.

Considering how important a thermostat is to your home, you should know its power source. Without the right power source, your unit will not work. Some models are battery-operated, whereas some are connected to your home’s power supply.

When the thermostat is connected to your main power supply, it will keep working as long as there is electricity. Whenever there is a power outage it will not work. If your thermostat uses batteries, it continues to work whether there is electricity or not. However, batteries have a limited lifespan.

Remember not all Lennox thermostats have batteries. For instance, the ComfortSense 5500 and Lennox Comfort S30 do not require batteries. Their power source is DC/AC. Some models such as Lennox ComfortSense 3000 are powered by a battery.

Lennox ModelPower SourceDoes It Require Battery
Lennox ComfortSense 7500ElectricNo
Lennox 15Z69 iComfort M30ElectricNo
Lennox iComfort 10F81AC/DCYes
ComfortSense 5500AC/DCNo
Lennox ComfortSense 3000AC/DCYes
Lennox iComfort S30AC/DCYes

How Do I Know If My Thermostat Uses Batteries?

You can know whether your thermostat is using batteries by checking its manual. In most cases, it will indicate the type of battery required. Most thermostats use AAA or AA alkaline batteries, 9V batteries, and lithium batteries.

If there is no manual, you should check the product description online. Also, you can check the back of the thermostat. If your unit is battery-operated, it will have a battery compartment. Make sure you check the type of battery size and its type.

Another way to tell whether your thermostat uses a battery is by looking at the screen. There is an icon that displays the battery level. Additionally, this will also indicate when the battery requires replacement. A “low battery” warning will appear on the display. Usually, it will appear for about 30 days before the battery dies. Make sure you replace the battery in time otherwise the thermostat would stop operating and shut down.

How do I change the batteries in my Lennox thermostat?

It is advisable to replace the battery of your thermostat each year. You should also consider replacing the batteries of CO detectors. Before you replace the battery, make sure you have the required tools and hardware. Ideally, you need a screwdriver and a level. In addition, you should have appropriate batteries for your model.

Follow these steps to replace batteries in a Lennox thermostat:

  1. Turn off your Lennox thermostat
  2. Slide the housing of your thermostat up and off the mounting. If it does not slide up, you can pull it off. Care should be taken to avoid damaging your thermostat.
  3. Check the back of your Lennox unit to see the battery required. Using a screwdriver remove the cover and then the battery.
  4. Check the direction of positive and negative signs of AAA or AA batteries. Insert your new batteries in the right slot. Most Lennox thermostats use AAA alkaline batteries.
  5. All programming details such as time, date, and schedule are retained even after changing the batteries. If they are lost, you should re-program them.
  6. Adjust the mounting plate to ensure it is firmly mounted to your wall. If it is loose, you can tighten it with a screwdriver.

Note: Some old thermostats might be using mercury. If that is the case, you should handle it well. Remember that mercury is poisonous and needs to be disposed of safely. If you have an old thermostat, you should upgrade to a modern, energy-saving smart thermostat.

It is advisable to change the batteries whenever you see the “Low Voltage” warning to ensure your heating and cooling system continues to work properly. If you fail to change the battery, you are likely to experience excessive heating or cooling in your home. Also, the HVAC system might fail to work.


Where are the batteries in a thermostat?

Usually, the batteries are placed at the back of the thermostat or behind the control panel. In most cases, you will need to open the cover to see the batteries.

How Do You Change the Battery In A Lennox Icomfort?

Start by turning off your thermostat. You can then unscrew the cover to remove the batteries. After removing the old batteries, you can then place new ones. Replace the cover and then turn on your thermostat.

What is the Battery Life of a Thermostat?

Some thermostat batteries can be up to 6 years, whereas others last for only 6 months. Even when the thermostat is hardwired, it might need a battery backup that should be replaced regularly. The battery backup is meant to ensure the system functions as required during power failure.

Wrapping Up

Lennox provides a range of thermostats. Not all of them require batteries. However, many models do and if you need to change the battery, you should first determine its type. Some thermostats are powered by lithium batteries or alkaline batteries. Whenever there is a power outage, the battery keeps the thermostat safe. Also, it prevents your HVAC system from going off.


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