If you can hear your furnace turning off and on constantly and you’ve noticed your energy bill creeping up, you’ve probably fallen victim to short cycling. There are a few main reasons why your system is cycling.
This is the most common cause of short cycling. A dirty filter restricts air flow from reaching your furnace’s heat exchanger. This can cause your furnace to overheat and shut down. It will begin turning off and on in response to the lack of air.
If your thermostat is too close to a heat source, it will respond to the temperature and turn off the furnace and then turn it back on when it realizes the room is cool. Your thermostat needs to be near an area that correctly represents the temperature of the room.
Blocked exhaust vents can be blocked by debris from outside. If an animal decides to make a nest in your vent, gases will build up causing your furnace to overheat and shut down. Make sure to shut off your furnace before you shine a flashlight into your exhaust vent to see if any critters have made a new home.