Why There's A Small Blinking Light On Your Thermostat

It can be frightening when lights start to blink on the mechanical devices we absolutely need. Whether it's your car's "check engine" light or your thermostat, a blinking light is often a sign that something needs your attention right away. The problem is, the light doesn't always tell you what is wrong, only that something needs to be fixed. When your thermostat is blinking, it usually means you need to change the batteries. If there's a little red light flashing, it potentially means something more serious is going on. 

Thermostats can usually go about a year before needing new batteries, and if you forget to add this to your annual maintenance, you may start to notice a blinking light. Some thermostats have a flashing battery indicator, while others rely on a simple blinking light. When there is no indication of what it could mean, changing the batteries is the first thing you should try. Simply swap out the old batteries for fresh ones and see if that fixes the problem. If the light is still blinking after you replace the batteries, it may be signaling another issue, especially if the blinking is accompanied by other warning signs from your HVAC system you shouldn't ignore, like unusual noises.

Depending on your thermostat, you may be able to get a better sense of what is wrong based on the number of flashes in a set time. For example, certain models are designed to blink three times in quick succession when an ignition failure occurs. If that's not true for your unit, another way to determine the problem is to turn off your system and your thermostat for a minute or so. If the blinking stops, it could have been a basic circuitry error.

If the light persists, you may want to inspect your AC unit or your heater. Check your circuit breaker, air filters, and the wires as well. To prolong the life of your HVAC system, you should change air filters every three to 12 months and have a professional inspection annually, but sometimes things can still go wrong. 

In the event that you've checked all the basics and the thermostat light is still blinking, you'll probably want to call an HVAC technician. Since persistent blinking potentially means that something serious needs to be fixed, it's best to address it before it becomes worse. Even if you're pretty handy, you'll probably want to avoid any HVAC DIYs you might regret. There are a lot of ways you could end up damaging your system instead of fixing it.