When a gas furnace turns on and off in short cycles, it can cause damage to the unit, higher heating costs, and fluctuating temperatures that, in turn, lead to an uncomfortable indoor environment. But why might a gas furnace cycle on and off quickly? And, more importantly, are there ways to troubleshoot this issue? Here’s what you need to know.

3 Reasons Your Furnace Is Turning Off & On

1. Overheating

Overheating is a common cause for a short-cycling gas furnace. When the unit gets too hot, the heat exchanger automatically shuts the appliance off to cool down. Then, once cool, it starts back up again. During the cooler months of the year, this cycle can occur quite fast. Overheating is often the result of clogged or dirty air filters or closed or blocked air vents, which, fortunately, are quick issues to remedy.

2. Malfunctioning Thermostat

A thermostat tells the furnace when to cycle on and off, making it a frequent source of trouble. Perform a quick inspection of the thermostat. If the screen is blank or the display unusual, change the batteries out and see if that fixes the problem. If not, there could be a wiring issue that needs professional attention. Also, if a thermostat is located too close to the furnace itself, it may not be giving an accurate temperature reading of the rest of the house and could cycle on and off faster; if this is the case, consult a professional about moving the thermostat to a more appropriate location.

3. Size of the Gas Furnace

The size of the unit could also play a role in causing briefer cycles. If a furnace is too big for the space it has to heat, it will naturally heat up, shut off, and then heat up again that much faster. Have an HVAC contractor perform a Manual J load calculation to see if your unit is the right size for the space it has to heat.

The heating contractors at Donovan & Jorgenson of New Berlin, WI, have been providing gas furnace repair and maintenance to area homeowners since 1985. Rated A+ by the BBB®, they have three locations in Greater Milwaukee to better serve you. Visit them online or message them on Facebook or Twitter to schedule an appointment today.