What To Do If My Furnace Keeps Turning Off


Furnace malfunctions are a common problem in the wintertime, especially with an older unit. If your furnace is turning on and off every few minutes, this is an issue called “short cycling.” While it’s normal for furnaces to turn on and off throughout the hour, short cycling happens much more often than normal function requires. Be sure to address this malfunction right away to avoid higher energy bills as well as damage to the furnace. However, you may want to know the potential causes of short cycling. Here’s what to look for.

Your Furnace Has Poor Airflow

The culprit for short cycling tends to be an airflow problem that prevents the furnace’s heat exchanger from cooling itself down properly. The unit’s safety mechanism kicks in and turns off the furnace to protect the system from overheating. If the air filter is clogged with accumulated dirt, turn off the furnace and replace your disposable filter with a new one. If the filter is reusable, vacuum away any debris or rinse it carefully with water. The other common causes for poor airflow — a dirty blower wheel or dirty flame sensor — do require professional maintenance. In these cases, you can rely on Guaranteed Comfort Heating & Cooling to clean the unit and restore your furnace to working condition.

A Malfunctioning Thermostat

Another common cause of short cycling is that the furnace is getting the wrong information from its thermostat. Low batteries in your smart thermostat can often cause these faulty readings, or your thermostat may be too close to a heat-producing source, such as a lamp. Inspect your thermostat to verify it’s not directing the furnace to short cycle.

An Oversized Furnace

Your furnace has to be the right size for your home to disperse the heat efficiently. An overly large unit will cycle between turning off and then quickly turning on again as the sensor notices the temperature drops. This cycle can lead to overuse and the premature breakdown of the furnace. The professionals at Guaranteed Comfort Heating & Cooling can ensure you have the right-sized furnace that fits your home’s needs.

If your troubleshooting efforts haven’t fixed the problem, contact Guaranteed Comfort Heating & Cooling in Windsor, ON, today. Our experienced technicians will diagnose your furnace issues and provide you with quality service. We also work with cooling systems.

Chris Egan


Chris Egan, owner of Guaranteed Comfort Heating & Cooling, brings over 35 years of HVAC experience. Dedicated to customer satisfaction, he delivers top-notch heating and cooling solutions.