Once the weather begins to cool off, you might be wondering about how you’ll prepare your heating and cooling. After all, HVAC bills routinely contribute a large portion of your monthly electric bill. To learn new ways to lower their HVAC bill, some people look closely at their thermostat. Maybe there’s a setting they should use to boost efficiency?

The bulk of 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 should help. We’ll review precisely what the fan setting is and how you can use it to save money during the summer or winter.

What Is the Fan Setting on My Thermostat?

For the majority of thermostats, the fan setting signifies that the system's blower fan stays on. A few furnaces will generate heat at a low level with this setting, but in most cases heating or cooling isn’t being produced. The ‘Auto’ setting, conversely, will start the fan during a heating or cooling cycle and turn it off when the cycle is finished.

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

Advantages to utilizing the Fan/On setting:

  • You can keep the temperature in each room more uniform by permitting the fan to keep circulating air.
  • Indoor air quality can increase since constant airflow will keep passing airborne pollutants into the air filter.
  • Fewer 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 prevent the need for furnace repair.

Drawbacks to utilizing the Fan/On setting:

  • A nonstop fan will likely increase your energy bills somewhat.
  • Continuous airflow can clog your air filter in a shorter amount of time, increasing the frequency you should replace it.

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

Through the summer, warm air may linger in unfinished spaces like the attic or an attached garage. If you use the fan setting, your HVAC system might draw this warm air into the rest of your home, compelling the HVAC system to work harder to maintain the preferred temperature. In extreme heat, this can result in needing AC repair more often as wear and tear grows.

The opposite can happen over the winter. Cooler spaces like a basement will hold onto cooler air, which may eventually drift into the rest of your home. Keeping the fan on 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 use 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 ideal for you if:

Someone in your household deals with allergies. Allergies and other respiratory conditions can be hard on the family. Leaving the fan on is more likely to enhance indoor air quality, helping your family breathe easier.

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