What Are the Advantages of a Furnace Temperature Sensor?

November 09, 2021

All gas and oil furnaces have an assortment of switches and controls that make them operational and safe. There is a furnace temperature sensor that controls your indoor temperature and others that assure your safety.

Indoor Temperature Control

The switch your furnace uses to control the temperature works with the thermostat to ensure your comfort. The furnace temperature sensor switch sends a message, either wirelessly or through a dedicated wire, to the thermostat that tells it when to turn on and off. Without the thermostat, you'd have to manually turn the furnace on and off.

Furnace Safety

One of the most important switches in any furnace, regardless of age, is its high-temperature switch. This gas igniter switch sends a message to turn the furnace off when the burner inside the furnace gets too hot. This can happen when the furnace isn't getting enough airflow over the heat exchanger.

The most common trigger for low airflow is a dirty air filter. When dust blocks some or all of the flow of air through the filter, the burner can't cool off, so it will overheat all the other parts inside the system. Besides harming the furnace and all its parts, it could create dangerous heat inside or near the furnace itself.

There is also a furnace temperature sensor that tells the system to turn the blower fan on. Without this sensor, your furnace fan would start blowing air before the heat exchanger had a chance to warm up. You'd experience a longer period of cold air coming from the ducts without this switch.


Old furnaces and those without electronic ignition use a sensor called a thermocouple. These systems rely on a pilot light to ignite the fuel when heat is called for. If the pilot light goes off, the thermocouple cools off and automatically shuts off the fuel supply. This prevents a buildup of gas or oil indoors.

If you have any concerns about a furnace temperature sensor in your system, contact the pros at Aggressive Mechanical Contractors. We proudly serve homeowners in Monmouth County and the surrounding areas.