As the weather starts to cool off, you are probably thinking about how you’ll take full advantage of your heating and cooling. After all, HVAC expenses can make up a large chunk of your monthly electric bill. To figure out new ways to reduce costs, some people take a closer look at their thermostat. Could there be a setting they can use to boost efficiency?

The bulk of thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a typical cycle, what will the fan setting offer for your HVAC system? This guide will help. We’ll walk through what exactly the fan setting is and whether you can use it to save money during the summer or winter.

My Thermostat Has a Fan Setting?

For the bulk of thermostats, the fan setting indicates that the HVAC blower fan stays on. Certain furnaces may continue to operate at a low level in this setting, but in general heating or cooling isn’t being made. The ‘Auto’ setting, conversely, will run the fan during a heating or cooling cycle and shut it off after the cycle is finished.

There are benefits and drawbacks to trying the fan setting on your thermostat, and the ideal option {will|can|should]] depend on your personal comfort needs.

Advantages to using the Fan/On setting:

  • You can keep the temperature in every room more uniform by allowing the fan to keep circulating air.
  • Indoor air quality will be highest since constant airflow will keep moving airborne contaminants through the air filter.
  • A smaller number of start-stop cycles for the blower fan helps extend its life span. Since the air handler is often a component of the furnace, this means you might avoid needing furnace repair.

Downsides to using the Fan/On setting:

  • A constant fan could raise your energy costs slightly.
  • Constant airflow may clog your air filter in a shorter amount of time, increasing the frequency you should replace it.

{Choosing Between|Should My Thermostat Be on|Which Setting for My Thermostat? Fan or Auto in Each Season

Through the summer, warm air may persist in unfinished spaces like the attic or an attached garage. If you keep the fan running, your HVAC system can draw this warm air into the rest of your home, forcing the HVAC system to run longer to maintain the desired temperature. In severe heat, this may lead to needing AC repair more often as wear and tear grows.

The opposite can happen in the winter. Cooler spaces like a basement will hold onto cooler air, which will eventually drift into the rest of your home. Leaving the fan running could pump more cold air upward, increasing the amount of heating you need to stay warm.

If you’re still trying to determine if you should use the fan/on setting, don’t forget that every home and family’s comfort needs are not the same. Leaving the HVAC system’s fan on might be best for you if:

Someone in your household has allergies. Allergies and similar respiratory conditions can be hard on the family. Leaving the fan on is more likely to improve indoor air quality, helping your family breathe easier.

Your home has hot and cold spots. All kinds of homes deal with difficult hot and cold spots that quickly evolve to a temperature different from the rest of the house. The fan setting might help limit these changes by constantly refreshing each room’s airflow.