Thermostat Keeps Turning Itself Off? 5 Reasons Why

Thermostat Keeps Turning Itself Off

It’s the hub of your HVAC system so having a thermostat that keeps shutting itself off is going to cause you nothing but headaches.

If you got a headache, and you’re either wrapped in blankets to warm up or stripped-down as much as you can, hoping to cool down, you’re in the right place. I’ll guide you through the reasons why your thermostat is shutting off and offer solutions.

Keep reading, and hopefully, we’ll address your issue.

Why Your Thermostat Keeps Turning Itself Off

I think it’s a good idea to start with an understanding of how your thermostat works. Because there is a chance the thermostat turning off is just a symptom of a problem with another component of your HVAC system and not the thermostat at all.

As mentioned at the outset, your thermostat is the hub of your system. It sends signals to your heater, cooler, fan, humidifier, and so on, telling them to turn on /off, go faster/slower, or adjust up/down.

While a faulty thermostat can shut itself off, the chances are much higher that it’s shutting off in response to a problem at the other end.

Let’s start with reasons that are specific to your thermostat then move to other issues that could cause your thermostat to turn off.

1. Failing Batteries

Does your thermostat have batteries? If your LED screen goes blank, it’s easy to guess that the problem might be your batteries.

That’s not always true, though. Typically your thermostat is powered by the air handler or furnace, and a battery is just for backup power. That being said, a disconnect (or a wireless thermostat) with battery issues could be a culprit.

Even if your LED screen is still reading properly your batteries may have drained enough not to be able to communicate with your HVAC.

Solution. Check your batteries. The best way to do this is that the battery tester but if you don’t have one, simply install new batteries and see if that fixed the problem.

Hand Replacing Thermostat Batteries
Some systems are designed to shut off entirely if the connection to the thermostat is lost: your system will not kick back on until the thermostat’s battery is replaced.

2. Wiring Issues

Any damaged or loose wires connected to your thermostat can cause intermittent or permanent shutdowns.

Since damaged or loose wires can lead to even bigger problems—such as a fire—it’s good to rule out this issue.

Solution. Remove the faceplate of the thermostat and check the connections and the condition of your wiring. It’s probably a good idea to check connections at the other end as well, meaning at your furnace and other equipment.

Tighten anything wires that are loose and if anything appears to be burned or compromised in any way, contact a professional.

3. The Location of Your Thermostat

When your home was built and your HVAC installed, your thermostat would’ve been placed in the optimal location. If you’ve done any renovating or simply moved your thermostat, this may be the cause of it shutting down.

Solution. Here are some guidelines for the best location.

  • Out of direct sunlight. A thermostat that gets direct sunlight will also have false readings since it thinks the room is hotter than it really is. This will stop your furnace from kicking in when you need it and cause your air conditioner to run longer than necessary.
  • Away from anything that generates heat. This could include kitchen appliances, portable heaters, lamps, lighting fixtures, even electronics.
  • Close to doors or windows. Since open doors and windows cause drafts that can potentially cool down surrounding air, keep your thermostat away from them.
  • Close to outside walls. A wall connected to the outside can vary in temperature. Instead, the best place to install a thermostat is typically next to a return intake, as it gives you a good mixture of the space as the air travels back to the thermostat.

From here, we’ll move on to possible issues with your HVAC components that are causing your thermostat to turn off.

Programable Thermostat Correctly Installed In Living Room
The best placement for the thermostat is on a central interior wall, away from direct sunlight, air vents, the kitchen, hallways, windows, and doors

4. Lack of Airflow

Every HVAC system is unique in terms of the amount of airflow it needs to operate. A lack of sufficient air can cause different components to overheat or freeze, such as your blower motor or even the compressor on your air conditioning unit.

Common airflow blockages are caused by dirty air filters or clogged evaporator coils. In either case, the dust, dirt, or debris can cause damage.

Any of the above circumstances can cause your system to shut down and stop answering the call of your thermostat.

Solution. Regular maintenance is the key here. This includes the following.

Stay up to date with changing or cleaning your air filter, as per the manufacturer’s recommendations. This will ensure that enough air makes it to your fan.

If necessary, clean your evaporator coil. You can do this several ways, including using:

  • Compressed air
  • A brush
  • Commercial cleaners
  • Mild detergent and water

You can also follow the steps in the video below.

One last thing to check is that all your vents—both supply and return—are moving the amount of air they are designed to.

This means your vents should not be blocked and/or completely closed. Don’t have furniture blocking a supply vent on the wall and don’t completely close or block supply registers.

Any one of the above issues can make your blower motor work harder than it should and potentially burn it out. If it’s struggling, this can impact airflow as well, so make sure fan blades are clean and the motor is functioning properly.

Check out the following video for a walkthrough on how to clean your fan.

5. Short Cycling

Short cycling refers to situations where your furnace or air conditioner turns off sooner than it should. It can be the symptom of a bigger problem or the cause of the problem but either way, it needs to be addressed.

Some of the most common causes for short cycling include:

  • Clogged air filters
  • Improperly sized HVAC equipment
  • Refrigerant leaks

If you have a furnace or air conditioner that turns off too soon and then turns back on again in five or so minutes, and keeps repeating the cycle, it creates wear and tear on your equipment and will eventually damage it.

Solution. Air filters are the most common and the cheapest issue and fix. So check that first. However, if you feel you have low refrigerant or a refrigerant leak, it will need to be dealt with by a professional.


While there are several reasons why your thermostat might keep turning off, the good news is that in many cases it’s an easy, inexpensive fix.

To recap, these are the things you should look for.

Problems With the Thermostat ItselfOther Issues That Will Impact the Thermostat
Failing batteriesLack of airflow
Wiring issuesShort cycling
Thermostat location 

Hopefully, this information has helped you diagnose the problem with your system and you’re able to fix it.

While you’re here, why not check out our related posts below. Perhaps we can help you with something else.

Thanks for reading.

I've been helping homeowners with appliance repair since 2016. Starting out as an enthusiastic amateur, I've since worked with many Appliance, HVAC, and DIY experts over the last 7+ years. My mission is to help fix your appliances and prevent future issues - saving you stress, time, and money. Visit my author page to learn more! Read more