When the weather is cooling off, you are probably concerned about how you’ll prepare your heating and cooling. After all, HVAC costs frequently add up to a large piece of your monthly electric bill. To try and find ways to lower their HVAC bill, some homeowners look closer at their thermostat. Maybe there’s a setting they could use to improve efficiency?

The bulk of thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a normal cycle, what does the fan setting provide for an 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 during the summer or winter.

What Is the Fan Setting on My Thermostat?

For most thermostats, the fan setting means that the HVAC blower fan stays on. Certain furnaces will run at a low level with this setting, but in general heating or cooling isn’t being made. The ‘Auto’ setting, conversely, will start the fan during a heating or cooling cycle and turn it off when the cycle is complete.

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

Advantages to utilizing the Fan/On setting:

  • You can keep the temperature in every room more balanced by enabling the fan to keep generating airflow.
  • Indoor air quality will be highest since continuous airflow will keep moving airborne pollutants into the air filter.
  • A smaller number of start-stop cycles for the blower fan helps extend its life span. As the air handler is often part of the furnace, this means you might avoid needing furnace repair.

Disadvantages to utilizing the Fan/On setting:

  • A constant fan could increase your energy bills slightly.
  • Nonstop airflow could clog your air filter in a shorter amount of time, increasing the frequency you will want to replace it.

{Choosing Between|Should My Thermostat Be on|Which Setting for My Thermostat? Fan or Auto in Each Season

Through the summer, warm air can linger in unfinished spaces including the attic or an attached garage. If you leave the fan on, your HVAC system might gradually move this warm air into the rest of your home, pushing the HVAC system to work more to preserve the desired temperature. In severe heat, this could result in 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 will eventually drift into the rest of your home. Keeping the fan on may pump more cold air upward, increasing the amount of heating you need to remain 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 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 is more likely to improve indoor air quality, helping your family breathe easier.

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