As the weather is cooling off, you may be thinking about how you’ll make the most of your heating and cooling. After all, HVAC bills frequently add up to a large chunk of your monthly electric bill. To try and find ways to save, some people look closely at their thermostat. Maybe there’s a setting they can use to increase efficiency?

The majority of thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a normal cycle, what does the fan setting offer for the HVAC system? This guide should help. We’ll review just what the fan setting is and whether you can use it to reduce costs in the summer or winter.

How Do I Access the Fan Setting on My Thermostat?

For the bulk of thermostats, the fan setting means that the HVAC blower fan stays on. Certain furnaces will generate heat at a low level with this setting, but for the most part heating or cooling isn’t being produced. The ‘Auto’ setting, on the other hand, will run the fan during a heating or cooling cycle and switch it off once the cycle is complete.

There are advantages and disadvantages to trying the fan setting on your thermostat, and whether you do or don’t {will|can|should]] depend on your distinct comfort needs.

Advantages to trying 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 should improve since constant airflow will keep moving airborne pollutants through the air filter.
  • A smaller number of start-stop cycles for the system's fan helps extend its life span. Since the air handler is typically part of the furnace, this means you might avoid needing furnace repair.

Downsides to using the Fan/On setting:

  • A continuous fan could increase your energy costs by a small margin.
  • Nonstop airflow may clog your air filter in a shorter amount of time, increasing the frequency you should 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 will sometimes linger in unfinished spaces such as the attic or an attached garage. If you keep the fan running, your HVAC system may gradually move this warm air into the rest of your home, pushing the HVAC system to work more to keep up with the preferred temperature. In serious heat, this may result in needing AC repair more quickly as wear and tear grows.

The opposite can occur over 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 setting on could pump more cold air upward, increasing the amount of heating you need to stay warm.

If you’re still trying to decide if you should use the fan/on setting, keep in mind that every home and family’s comfort needs are different. Leaving the HVAC system’s fan on may be ideal for you if:

Someone in your household has allergies. Allergies and similar respiratory conditions can be hard 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. All kinds of homes deal with difficult hot and cold spots that quickly shift to a temperature different from the rest of the house. The fan setting can help minimize these changes by constantly refreshing each room’s airflow.