Is it possible to set a too hot furnace temperature? Suppose outdoor temperatures plummet one night; how far can you push the thermostat above the usual setting without damaging the furnace? These are valid questions as another winter here in western Ohio approaches and the HVAC thermostat is switched from cooling mode to heating mode.
Burner Temperature Vs. Airflow Temperature Vs. Thermostat Temperature
Hot air leaving the furnace burner is generally between 140 and 170 degrees Fahrenheit. By the time the airflow passes through the ductwork and enters a room at the supply vent, the temperature has typically dropped to about 120 to 140 degrees. As it blends into cooler air in the room, the airflow temperature drops rapidly.
Your thermostat doesn’t know the temperature of the furnace burner or the temperature of airflow. Those temperatures do not vary, no matter what the thermostat setting may be. Instead, the thermostat controls how long the furnace heating cycle runs by continuously sensing the room temperature. When the desired room temperature setting has been achieved, the thermostat shuts off the furnace.
Can You Damage a Too Hot Furnace?
Most thermostats won’t allow a programmed temperature setting higher than 90 degrees. So, even if you wanted to go hotter, the thermostat would not allow it. In addition, the furnace itself incorporates protection against damage caused by excessively high temperatures due to other issues, such as obstructed system airflow. The high limit switch inside the furnace continuously senses internal temperature. In most cases, if the furnace temperature exceeds a preset maximum, the limit switch will automatically shut off the burner to prevent damage to the unit.
What’s the Recommended Furnace Temperature Setting?
According to the Department Of Energy, the most efficient thermostat setting in winter is the range between 68 degrees and 72 degrees while the home is occupied. This provides the best balance between comfort and energy efficiency and avoids a too hot furnace.
For more answers to questions about a too hot furnace, contact the heating professionals at Detmer and Sons.