How to Tell If Your Home Thermostat is Bad or Broken


Can a thermostat go bad? In short, yes – but, good news, you can expect your home thermostat to last about a decade.

Thermostats don’t have a set lifespan, but the average thermostat should last around 10 years. After your thermostat has celebrated its tenth birthday, it might start to malfunction thanks to a decade of dust buildup and worn-out wiring.

Sometimes, however, your thermostat isn’t broken after all. But how can you tell? In this article, we detail signs your thermostat is actually broken and how to troubleshoot yours if it’s malfunctioning.

4 Signs of a Bad Thermostat

Be on the lookout for these signs, which may mean your thermostat is broken.

1. Your thermostat has no power

Is the display on your thermostat blank? Is there no change in your home’s temperature after you make an adjustment? If so, your thermostat may be broken. Best case scenario: the batteries might just need to be replaced!

2. Your AC or heater runs constantly but won’t turn off

If your AC or heater runs constantly but won’t turn off, the wiring may be frayed. This could also mean that the thermostat is miscalibrated.

3. Your AC or heat won’t turn on

If the display is lit, but your AC or heater won’t turn on, the wiring may be defective and preventing electrical signals from being sent.

4. Your home temperature isn’t what you want it to be

Sometimes when our air conditioning system doesn’t seem to be properly cooling or heating our home, we don’t think to look at the thermostat. Sometimes, a faulty thermostat is to blame for fluctuating temperatures in different parts of your home or inefficient cooling and heating throughout.

How to Troubleshoot a Bad or Broken Thermostat

Is your thermostat exhibiting one of the symptoms above? Fear not. Here’s how to troubleshoot a broken thermostat in five easy steps.

1. Check the Thermostat Setting

This step might seem obvious, but it’s easy to accidentally switch your thermostat to the wrong setting and not realize it – so do this first.

2. Replace the Batteries

Sometimes a “broken” thermostat just needs new batteries. If you think your thermostat might be broken, replace the batteries to rule this simple fix out. For good measure, replace batteries in digital thermostats once per year.

If your AC or heater won’t turn off, it may simply be because your thermostat is set to “ON” instead of “AUTO.” If the setting is correct, proceed to the next step.

3. Adjust the Thermostat to Five Degrees Lower or Higher

Depending on the season, try adjusting your thermostat to either five degrees warmer than usual (winter), or five degrees cooler than usual (summer). Once you adjust the thermostat either up or down, you should hear a click. Within a few minutes, your AC should begin to blow out air or suck air in. Once it kicks on, check the supply registers.

4. Clean Your Thermostat

If you have a mechanical thermostat (re: not digital), it might just need to be cleaned. Mechanical thermostats, in particular, can malfunction due to dust buildup. Simply remove the cover of the thermostat and dust inside using a small brush or cloth.

5. Test the Wire Connections

If none of the above have fixed your thermostat, the final step to inspect the wires and then test the wire connections. You can do this by removing the thermostat cover. Take a look at the wires and make sure they’re all connected to the correct mounting screw.

Thermostat Repair and Replacement In Titusville, Florida

If your thermostat is bad or broken, contact Colman Air for thermostat repair or replacement services. Our trusted technicians will help you find the right thermostat for your home’s unique needs and will provide a quick and efficient installation. Call us at (321) 360-7566.