Why Does My Furnace Shut Off Before Reaching the Temperature I’ve Set?

Has your furnace stopped blowing warm air before it reaches the target temperature? If you find yourself thinking, “Why does my furnace shut off before reaching the temperature I’ve set”? You are not alone. This is a very common furnace problem, and can be very frustrating if you are trying to maintain a comfortable indoor environment at just the temperature you like.

In this article, we’ll review some of the reasons your furnace may be shutting off before it reaches its target temperature.

Thermostat Problem

You may simply need a new thermostat to resolve your problem. This is especially true if you have an older dial-type thermostat, which may be calibrated incorrectly. It may also have become less accurate over time as its components age. Pick up a new thermostat and replace your older model to see if this solves the problem.

Sensor Problems

There may be something causing a sensor to turn off the furnace after reaching a certain temperature. A malfunctioning, blocked or dirty flame sensor could be the issue. Luckily, this is easily resolved by maintaining a regular furnace maintenance schedule to ensure your flame sensor stays free of dust and debris.

Blocked Airflow

A lack of airflow can cause your furnace to stop heating before reaching the set temperature. Ensure there is nothing impeding airflow around your furnace, within your furnace and through your ducts. Check that registers are open, no ducts are damaged or crushed and replace your furnace filter. Inside your furnace should be clean and free of debris, especially around the blower motor and the heat exchanger. Move any furniture, boxes or other objects away from the furnace itself.


If your furnace is overheating, it could be shutting off prematurely before it reaches your desired temperature when the temperature safety limit is reached. Ensure that your furnace filter is clean and there are no other obvious signs of broken or loose parts inside your unit. If the problem is still occurring, shut off your furnace and call a professional for service. An overheated furnace can be extremely dangerous and can cause further damage if the problem is not addressed.

Are you still wondering, “Why does my furnace shut off before reaching the temperature I want”? The HVAC team at Evam Canada can answer your questions and diagnose and repair any furnace issues you may be experiencing. It may also be time to consider upgrading your equipment. We offer heat pump installation services and 24/7 emergency heat pump repair. You can even check out any of the new government rebates for heat pump installations. To book an appointment, contact us online or give us a call at 905-624-5544.