does low battery affect thermostat

Does low battery affect thermostat? You may need to understand this concern so that you may not get frustrated once it happens to you.

Once your thermostat battery gets low, you will not have the system’s full functionality.

Please read below to understand how low batteries can affect your thermostat, and how you can know if the batteries are low.

When your thermostat batteries are low, your system will not work correctly. Your home will not heat or cool, and you will lose all settings during a power outage. In case you see any sign of low battery, replace them immediately.

Does Low Battery Affect Thermostat?

Yes. When your thermostat batteries are low, they will affect the way your thermostat functions.

You may ask why it should affect your thermostat, yet they are only a backup during power outages.

Can you imagine that your thermostat batteries are low and you have a power outage in your home?

This means that your thermostat will not run. So, the thermostat will not heat or cool your room.

Second, your thermostat settings will not be saved. Hence, you will have to begin afresh setting or programming your thermostat. So, how can you know that your thermostat batteries are low?

Symptoms of a Low Thermostat Battery

Your batteries cannot die entirely without showing you some signs. The symptoms of low-powered thermostat batteries include:

  • You will see words like ‘low battery’ on the screen display of your thermostat.
  • A low battery symbol on the screen
  • Your unit will have a flashing light.
  • Some thermostats might include a beep.
  • The air conditioner or the heating system operates unreliably.
  • The display screen will go blank.

When the screen fails to display anything, then it means you overlooked all the first symptoms.

So, your batteries are completely dead, and your thermostat cannot work again until you replace the batteries.

Should I Replace My Batteries Immediately I See the Above Signs?

low battery affect thermostat replace

Your thermostat batteries should last up to a year. What about if your batteries are not yet this period old, but you see those signs? Should you replace the batteries?

Yes, the moment you see any of the above symptoms, it is time to replace your thermostat batteries.

Otherwise, your thermostat will not operate normally. Your room might be extremely hot or too cold. So, does low battery affect home thermostat?

The answer is Yes!

Also, if you think that your batteries are draining too fast, you may need to replace the batteries.

The batteries you go for should be AA or AAA alkaline batteries or those with higher voltages.

These kinds are known for their high-quality and durability features. Any other type might give you a hard time and make you spend more because they will drain quicker.

What If Thermostat Do Not Give Signs of Low Battery?

Some thermostats may not give you signs that the battery is low. Instead, the thermostat will start behaving abnormally. For instance, the unit may beep unremittingly.

The system fails to operate in some instances, the display goes blank, and you cannot control the settings.

When any of these issues occur, check the batteries first, then replace them if necessary.

Also, if you know that the battery is past the recommended period of usage and you see the signs, kindly replace it.

Should My Thermostat Have Batteries?

Not all thermostats must have batteries. If yours has the battery slot behind it, it will need a battery.

However, some thermostats are hardwired and only need electrical power to run. If yours has no batteries, your settings will not be backed up when electricity is lost.

How Long Should Thermostat Batteries Last?

Most thermostat batteries last between eight months to one year. Some can even go up to two years.

What matters is the type of your thermostat and how you use your thermostat.

Note that if you keep turning your system on and off, the batteries will drain quicker. Before the unit turns on, it consumes lots of energy; hence the batteries drain quicker.

Once the eight months or one year elapses, you will need to replace your batteries.

Some thermostats have rechargeable batteries. If yours is one of them, you can recharge. If not, acquire brand new batteries.

Why Do My Thermostat Batteries Drain Quickly?

Could it be that your batteries give you low battery-sign quite quicker than they should?  It might be having issues like:

1. Corroded Contacts

If your thermostat has corroded contacts, it will have a high resistance short or loose connection.

It affects the battery since it speeds the current or voltage, hence decreasing the amperage.

The solution will be cleaning the corroded contacts, and your battery will work at the expected voltage without speeding its usage.

2. Your Thermostat is Old

When a thermostat becomes too old, the wires too age, and most parts accumulate dirt. The aged parts use too much energy, hence draining the battery quickly.

Even though there is no specific lifespan for most thermostats, consider replacing it if yours has lasted more than ten years.

3.  A Wrong Type of Battery

If you have recently replaced your thermostat batteries and you feel like they have drained quickly, it could be that you purchased the wrong type of batteries.

Most thermostats require batteries with 3.6 voltage batteries or more. If your batteries are 1.5 voltage or less, expect them to drain quicker.

What to Do When a Thermostat Fails to Work After Replacing the Batteries

Not all thermostats will show you low battery symptoms but fail to work.

So, you may be tempted to assume that the batteries are the issue; hence you will end up replacing them, but the system would still fail.

What could be the problem? Look out for these possible issues:

The Wires

The wires behind the thermostat may be loose. You will need to check them and tighten them to their terminals.

You can also remove the thermostat panel and confirm if the lights are working.

If the lights are on, it means that you have enough power going to the system. However, it is not reaching the thermostat.

A Blown Fuse

If your thermostat fuse is blown, it can cause the thermostat to fail to respond to commands.

Check the fuse on the main circuit board. You will find the number ‘3’ written on top of it. Confirm if it is blown. If so, you will have to replace it.

Clogged Pipe

Your AC condensation pipe might have dirt that has clogged it. If so, the safety valve will not allow power to flow to the thermostat.

So, your room will not cool nor heat. The solution is to unclog the pipe, then try turning on the thermostat.

Low batteries can affect your thermostat. First, the system will not effectively cool or heat your home. Also, the display may be blank; hence you cannot control the settings. Besides, all your settings will be lost when you have a power outage, and the batteries are drained.

Read Next: Why Thermostat Clicks but Nothing Happens?


Knowing how ‘does low battery affect thermostat’ is crucial since you will know what to do when the thermostat gives you the signs.

Please do not wait until the batteries drain completely to replace them.

Know that low batteries will affect your heating and cooling system. In case of a power outage, you will lose your thermostat’s settings.

Nicole B