Once the weather is cooling off, you might be wondering about how you’ll take full advantage of your heating and cooling. After all, HVAC expenses routinely contribute a significant chunk of your monthly electric bill. To try and find ways to save, some homeowners look closely at their thermostat. Maybe there’s a setting they could use to improve efficiency?

Most thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a normal cycle, what can the fan setting provide for your HVAC system? This guide should help. We’ll share just what the fan setting is and when you can use it to cut costs during the summer or winter.

Should I Use My Thermostat's Fan Setting?

For the majority of thermostats, the fan setting indicates that the HVAC blower fan remains on. Certain furnaces can run at a low level in this setting, but in most cases heating or cooling isn’t being made. The ‘Auto’ setting, conversely, will start the fan through a heating or cooling cycle and switch it off when the cycle is finished.

There are advantages and disadvantages to using the fan setting on your thermostat, and the ideal option {will|can|should]] depend on your distinct comfort requirements.

Advantages to trying the Fan/On setting:

  • You can keep the temperature in every room more consistent by allowing the fan to keep running.
  • Indoor air quality will be highest because constant airflow will keep passing airborne pollutants into the air filter.
  • Fewer start-stop cycles for the blower fan helps extend its life span. As the air handler is usually connected to the furnace, this means you might prevent the need for furnace repair.

Downsides to using the Fan/On setting:

  • A nonstop fan will likely add to your energy bills somewhat.
  • Continuous airflow can 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 Summer/Winter

During the summer, warm air will sometimes persist in unfinished spaces such as the attic or an attached garage. If you keep the fan running, your HVAC system may draw this warm air into the rest of your home, forcing the HVAC system to work more to keep up with the preferred temperature. In extreme heat, this may result in needing AC repair more often as wear and tear gets worse.

The opposite can take place in the winter. Cooler spaces like a basement will hold onto cooler air, which may eventually flow into the rest of your home. Leaving the fan setting on will sometimes pull more cold air upward, increasing the amount of heating you need to stay warm.

If you’re still trying to determine if you should switch to the fan/on setting, keep in mind that every home and family’s comfort needs will vary. Leaving the HVAC system’s fan on may be best for you if:

Someone in your household has allergies. Allergies and other respiratory conditions can be hard on the family. Leaving the fan on can help to enhance indoor air quality, helping your family breathe easier.

Your home has hot and cold spots. Lots of homes deal with stubborn 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 steadily refreshing each room’s airflow.