When the weather begins to cool off, you may be thinking about how you’ll prepare your heating and cooling. After all, HVAC bills frequently add up to a significant chunk of your monthly electric bill. To try and find ways to save, some owners look closer at their thermostat. Maybe there’s a setting they should use to boost efficiency?

Most thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a regular cycle, what does the fan setting provide for your HVAC system? This guide can help. We’ll walk through what exactly the fan setting is and whether you can use it to cut costs over the summer or winter.

What Is the Fan Setting on My Thermostat?

For the bulk of thermostats, the fan setting signifies that the HVAC blower fan keeps running. Certain furnaces may continue to run at a low level in this setting, but for the most part heating or cooling isn’t being generated. The ‘Auto’ setting, on the other hand, will start the fan through a heating or cooling cycle and turn it off after the cycle is finished.

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

Advantages to trying the Fan/On setting:

  • You can keep the temperature in every room more balanced by enabling the fan to keep circulating air.
  • Indoor air quality will be highest because constant airflow will keep moving airborne contaminants through the air filter.
  • Fewer start-stop cycles for the blower fan helps expand its life span. As the air handler is usually connected to the furnace, this means you can prevent the need for furnace repair.

Downsides to using the Fan/On setting:

  • A nonstop fan could add to your energy costs somewhat.
  • Constant airflow could clog your air filter up more quickly, 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 can stick around in unfinished spaces like the attic or an attached garage. If you leave the fan on, your HVAC system may draw this warm air into the rest of your home, forcing the HVAC system to run longer to maintain the preferred temperature. In serious heat, this can result in needing AC repair more quickly as wear and tear gets worse.

The opposite can take place over the winter. Cooler spaces like a basement will hold onto cooler air, which will eventually flow 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 determine if you should try the fan/on setting, keep in mind that every home and family’s comfort needs are not the same. Leaving the HVAC system’s fan on could be best for you if:

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

Your home experiences hot and cold spots. Lots of homes deal with persistent hot and cold spots that quickly evolve to a temperature different from the rest of the house. The fan setting should help minimize these changes by consistently refreshing each room’s supply of air.