As the weather begins to cool off, you might be concerned about how you’ll make the most of your heating and cooling. After all, HVAC costs frequently add up to a significant chunk of your monthly electric bill. To learn new ways to lower their HVAC bill, some homeowners look closely at their thermostat. Could there be a setting they could use to improve efficiency?

Most thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a normal cycle, what does the fan setting offer for your HVAC system? This guide can help. We’ll walk through just what the fan setting is and whether you can use it to save money in the summer or winter.

How Do I Access the Fan Setting on My Thermostat?

For most thermostats, the fan setting signifies that the HVAC blower fan keeps running. Certain furnaces can operate at a low level with this setting, but in most cases heating or cooling isn’t being produced. The ‘Auto’ setting, conversely, will turn on the fan over a heating or cooling cycle and shut it off once the cycle is complete.

There are benefits and drawbacks to trying the fan setting on your thermostat, and whether you do or don’t {will|can|should]] depend on your unique comfort preferences.

Advantages to switching to the Fan/On setting:

  • You can keep the temperature throughout your home more balanced by enabling the fan to keep generating airflow.
  • Indoor air quality should improve since continuous airflow will keep forcing airborne pollutants into the air filter.
  • A smaller amount of start-stop cycles for the blower fan helps lengthen its life span. Because the air handler is usually a component of the furnace, this means you could avoid needing furnace repair.

Drawbacks to using the Fan/On setting:

  • A continuous fan will likely raise your energy bills somewhat.
  • Continuous airflow could clog your air filter soon, increasing the frequency you will want to replace it.

Which Setting for My Thermostat? Fan or Auto in Summer/Winter

During the summer, warm air will sometimes linger in unfinished spaces such as the attic or an attached garage. If you leave the fan on, your HVAC system may gradually move this warm air into the rest of your home, forcing the HVAC system to run longer to keep up with the desired temperature. In severe heat, this can result in needing AC repair more quickly as wear and tear gets worse.

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

If you’re still trying to figure out if you should use the fan/on setting, don’t forget that every home and family’s comfort needs will vary. Leaving the HVAC system’s fan on could be ideal for you if:

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

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