Signs Your Thermostat Is Malfunctioning

Man in a sweater adjusting his thermostat

You have your thermostat set to a nice, comfortable 73, but you're reaching for a sweater. This could be a sign that your thermostat is malfunctioning, or that something else is going on which means you need AC repair.

 

A surprising number of problems with AC systems are caused by the thermostat. Thankfully, thermostats are a cheap component of the system and easily repaired or replaced. So, how do you know if your thermostat has a problem? Here's a quick list of things to consider:

  • Is your thermostat set correctly? Did the kids switch it from heat to cool or vice versa? It might seem dumb, but it happens to all of us. Making sure that your thermostat is actually set the way you intended it is the first step.
  • Is your furnace or air conditioning system working properly? Check the main circuit breaker hasn't thrown and that the system is getting power.
  • Adjust your thermostat five degrees higher in heating season or lower in the cooling season and see if anything turns on. Sometimes systems can get "stuck" and become non-responsive. The problem might also be in a fan somewhere. Your thermostat may be reading the incorrect temperature and thus, not cutting in when it needs to.
  • Check to see if air of the appropriate temperature is flowing. If your air conditioner is blowing warm air and the thermostat is set correctly, it is most likely a problem with the system, but it could be your thermostat. If the unit is not blowing any air at all, try setting the fan to "on" rather than "auto." If air starts blowing at that point then it's worth checking the thermostat.
  • Make sure nothing is messing with your thermostat. Your thermostat should not be over a TV (especially an older CRT TV) or a lamp that still uses incandescent bulbs. It should not be near a heat source, in a direct draft, or wedged in a corner with no airflow. If any of these are true, you need to move your thermostat, which you may or may not need an electrician's help with.
  • Check the batteries. Some electronic thermostats have batteries which can, of course, wear out. It's worth simply replacing the batteries and seeing if that fixes the problem. Make sure that you know how to remove the cover properly, look at the owner's manual if unsure. Most thermostats use either AA or AAA alkaline batteries or 3V button-style lithium batteries (similar to those used in a watch). Your owner's manual will tell you which type of battery you need.
  • With mechanical thermostats there's a heat anticipator under the cover, generally marked "longer." If your furnace is cutting in and out, move it longer. If your room temperature is fluctuating, move it the other way.

Thermostat repair is seldom worth it. If none of the above work, you should get your thermostat checked by a professional, but be prepared to replace, rather than repair, the thermostat. If you have an older mechanical thermostat, it may be worth replacing it with a digital or smart thermostat anyway. Digital thermostats reduce energy costs considerably, and programmable thermostats are even better.

If the issue is not your thermostat, then you need proper AC repair to solve the problem. In many cases, however, the troubleshooting above will resolve the problem. When it does not, call American Air Cares.

If you have a malfunctioning thermostat or any other AC or heating problems, contact American Air Cares. We offer AC repair services in Stuart and Port St. Lucie, and can easily diagnose and fix issues with your thermostat.