Broken Thermostat? Here Are Quick Fixes You Can Try

When your home furnace or AC unit doesn’t work the way it should, you might have a malfunctioning thermostat. Beyond causing discomfort, using a broken thermostat could also lead to wasting a lot of energy. Here are ways you can tell if the thermostat is broken, as well as simple DIY fixes you can try before calling an HVAC service near you.

How to Know if Your Thermostat is Broken

Your thermostat controls your HVAC system. If it is broken, your furnace, AC unit, and whole-house fan won’t work either. Common signs of broken thermostats include:

  • A non-responsive thermostat display
  • A faded or incomplete readout on the screen
  • Non-responsive furnace or AC, even after adjustment
  • The AC or heat stays on even after you’ve reached the desired temperature
  • The AC or heat turns off before you reach the temperature you set
  • Different rooms have different temperatures

Before calling professionals, you can try some do-it-yourself remedies for your HVAC system. Here are things that might fix your AC and heater:

Switch the Power Circuit On

Sometimes people don’t realize that their “broken” AC or heater is just turned off. Before calling an HVAC service provider, check if your system components are running—examine your circuit breakers and see if they have been tripped. If they have, try switching them on.

You can also try setting the temperature five degrees above or below normal. There should be a click when you turn the temperature up or down. Also, wait a few seconds to see if the supply and room vents blow out or suck in air as they should.

Replace the Thermostat Batteries

After checking the circuit breaker, see if the thermostat’s control panel is working correctly. Perhaps all you need to do is replace the batteries on your digital thermostat. In many homes, this is enough to resolve thermostat issues.

Clean the Thermostat

If the power and the control panel batteries are not the problem, you could check if your thermostat needs cleaning. Nicotine buildup, dust, dirt, and other pollutants can affect the way an HVAC system works. Some thermostats open quickly, allowing you to reach in and clean the inside. Others would need you to unscrew the faceplate. 

When cleaning your thermostat, use soft tools like dry, clean paintbrushes. You can also blow compressed air into the panel—note that you should follow the safety instructions on the can. Also, remove the batteries and turn the unit off before you clean the thermostat.

What to Do if the Thermostat Needs Replacing

If none of these quick fixes work, you could consult a heating and air conditioning professional on what you should do next. One thing they could suggest is for you to get a new thermostat. Some homeowners, especially those with electrical knowledge, could install these items themselves. However, if you don’t know how to install a thermostat, it’s best to leave this to someone knowledgeable.


If you don’t want to install a new thermostat, you should still hire an HVAC service provider to do the job. Testing wire connections would be more challenging with newer, high-tech thermostats which have complex setups. You might injure yourself repairing this type of device. What’s more, it might not work. It will cost more for a technician to repair and reinstall it, which means even more expenses on your end. You might even void your warranty if you repair your thermostat yourself.

Keep your cool and take home maintenance in stride when you hire Air 1 Heating & Cooling. We are a heating and air repair company in Short Hills, Millburn, Summit, and Chatham, NJ, specializing in air conditioning maintenance and repair, coil cleaning, Wi-Fi and standard thermostats, furnace and heating maintenance, and more. Request a free estimate today!