If you’ve been reading our blog regularly, you’ve probably seen us refer to the thermostat as the “brain” of your HVAC. That’s not just to say it controls the other units that make up your HVAC system — it’s also a reminder that without a working thermostat, none of that hardware will function. As such, air conditioner thermostat problems can be a significant source of consternation for the HVAC owners who face them. Fortunately, we can provide you with all the information you need to take excellent care of your thermostat and resolve problems with it as soon as possible.
Below, we’ve provided information on five of the most common air conditioner thermostat problems we encounter in our work. Learn how to identify and address these issues so that you’ll enjoy better service from your thermostat all summer!
Five Air Conditioner Thermostat Problems You Need to Look Out For
- Programming Issues: the first thing you should understand about the thermostat in your HVAC is that it needs to be programmed properly. 90% of Americans have barely ever tried to program their thermostat themselves because they don’t have confidence in their abilities to do it correctly. However, leaving the factory settings on a thermostat when you purchase one and have it installed is almost never the most energy-efficient way to use it, and it can cause you to face higher energy bills than necessary.
For best results during the warmest part of the year, set your thermostat to 78 degrees during the hours you spend inside the house, and manually shut down the AC on any days when you don’t require cooling. You can also give your thermostat an efficiency boost by programming it to shut down the air conditioner 20 to 30 minutes before you leave the house for work each day, and to turn it back on 20 or 30 minutes before you return.
- Power Supply Problems: improper thermostat programming accounts for many energy-efficiency problems with an air conditioner, but what if the thermostat display screen is entirely blank? You might be inclined to panic, but don’t — there’s a significant chance it’s just a battery problem. The first thing you should do is replace the battery and see if that solves the problem.
If you’re still experiencing inconsistent performance, check the batteries to make sure they’re AA Lithium batteries instead of Alkaline ones. Alkaline batteries drain faster, resulting in spotty performance and even leakage that can damage the system.
- The Thermostat Isn’t Level: this isn’t a problem for most newer thermostats, but if you own an older model it might use a mercury switch. Mercury switches respond to temperature changes in a room with a coil that either contracts or expands, tilting a mercury-filled glass bulb in the process. In turn, the position of the mercury either opens or closes the circuit, causing the cooling system to turn on or off.
These older thermostats must be level for the mercury in the bulb to tilt correctly and move to the appropriate position. If your thermostat has been installed at an angle — even a slight one — it could prevent your system from turning on or off at the correct times.
- Faulty Wiring: the circuit connecting the thermostat to the air conditioner can be broken in other places as well, even in newer systems. If the wires that run between these systems are damaged, loose, or particularly old it can spell trouble for your AC performance. It’s best to call a licensed HVAC professional if you suspect problems with the wiring in your HVAC — and possibly an electrician too, depending on their recommendation. Electrical issues can be difficult (and dangerous) to tackle by yourself without the proper tools and knowledge.
- The Thermostat is Installed in the Wrong Place: thermostat placement is another of the most common culprits we’ve encountered when sussing out the trouble with different systems. Remember: your thermostat has to read the temperature in the room where it’s installed before it can send information to your HVAC and adjust it accordingly. If the sensor in your thermostat is too close to something that’s throwing off its ability to read the rest of the room, the performance your HVAC delivers will be based on the temperature in that specific area instead of the temperature throughout the room itself.
Make sure your thermostat isn’t installed next to a fireplace, radiator, heat-producing appliance, or any outside doors and windows. If it is, you might want to consider re-installing it in another location seriously.
Air conditioner thermostat problems are generally caused by fairly simple oversights, but that also means we tend to overlook them. Make sure to check your thermostat for any of the issues listed above and take the appropriate steps to solve any that you find.