As the weather begins to cool off, you may be concerned about how you’ll prepare your heating and cooling. After all, HVAC expenses frequently make up a big piece of your monthly electric bill. To learn new ways to lower their HVAC bill, some homeowners look closer at their thermostat. Is there a setting they can use to boost efficiency?

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

Should I Use My Thermostat’s Fan Setting?

For the bulk of thermostats, the fan setting indicates that the air handler’s blower fan remains on. Certain furnaces may continue to run at a low level in this setting, but for the most part heating or cooling isn’t being made. The ‘Auto’ setting, in contrast, will start the fan during a heating or cooling cycle and turn it off after the cycle is finished.

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

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 can increase because continuous airflow will keep forcing airborne particles through the air filter.
  • A smaller amount of start-stop cycles for the HVAC fan helps expand its life span. Since the air handler is often part of the furnace, this means you can minimize the risk of needing furnace repair.

Drawbacks to utilizing the Fan/On setting:

  • A constant fan could add to your energy expenses slightly.
  • Continuous airflow may clog your air filter in a shorter amount of time, increasing the frequency you’ll need to replace it.

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

Through the summer, warm air will sometimes stick around 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 work harder to preserve the set temperature. In serious heat, this may lead to needing AC repair more often as wear and tear gets worse.

The reverse can occur in the winter. Cooler spaces such as a basement will hold onto cooler air, which can eventually drift into the rest of your home. Leaving the fan running may pump more cold air upward, increasing the amount of heating you need to remain warm.

If you’re still trying to decide if you should use the fan/on setting, remember 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 suffers from allergies. Allergies and similar respiratory conditions can be stressful 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. Many homes wrestle with difficult hot and cold spots that quickly shift to a temperature different from the rest of the house. The fan setting should help lessen these changes by constantly refreshing each room’s supply of air.