As the weather begins to cool off, you are probably thinking about how you’ll make the most of your heating and cooling. After all, HVAC bills frequently contribute a big portion of your monthly electric bill. To learn new ways to save, some owners look closely at their thermostat. Is there a setting they could use to increase efficiency?

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

What Is the Fan Setting on My Thermostat?

For the bulk of thermostats, the fan setting signifies that the system's blower fan stays on. Certain furnaces can run at a low level in this setting, but in general heating or cooling isn’t being produced. The ‘Auto’ setting, conversely, will run the fan during a heating or cooling cycle and switch it off after the cycle is complete.

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

Advantages to using the Fan/On setting:

  • You can keep the temperature in each room more consistent by allowing the fan to keep running.
  • Indoor air quality can increase because constant airflow will keep passing airborne contaminants into the air filter.
  • A smaller number of start-stop cycles for the blower fan helps expand its life span. Because the air handler is typically connected to the furnace, this means you could avoid needing furnace repair.

Drawbacks to using the Fan/On setting:

  • A nonstop fan will likely add to your energy costs slightly.
  • Constant airflow may clog your air filter in a shorter amount of time, increasing the frequency you will want to replace it.

Should My Thermostat Be on Fan or Auto in Summer/Winter

During the summer, warm air can linger in unfinished spaces including the attic or an attached garage. If you keep the fan running, your HVAC system might pull this warm air into the rest of your home, forcing the HVAC system to run longer to preserve the preferred temperature. In serious heat, this can result in needing AC repair more regularly 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 make its way into the rest of your home. Leaving the fan running could draw more cold air upward, increasing the amount of heating you need to remain warm.

If you’re still trying to figure out if you should use the fan/on setting, remember that every home and family’s comfort needs are different. Leaving the HVAC system’s fan on could be best for you if:

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

Your home has hot and cold spots. Many homes wrestle with difficult hot and cold spots that quickly evolve to a temperature different from the rest of the house. The fan setting can help lessen these changes by steadily refreshing each room’s ventilation.