As the weather is cooling off, you might be wondering about how you’ll prepare your heating and cooling. After all, HVAC expenses routinely add up to a significant chunk of your monthly electric bill. To figure out new ways to lower their HVAC bill, some owners take a closer look at their thermostat. Is there a setting they should use to boost efficiency?

The bulk of thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a regular cycle, what does the fan setting provide for an HVAC system? This guide can help. We’ll share what exactly the fan setting is and when you can use it to cut costs during the summer or winter.

What Is the Fan Setting on My Thermostat?

For most thermostats, the fan setting indicates that the air handler’s blower fan keeps running. Certain furnaces can operate at a low level with this setting, but in general heating or cooling isn’t being produced. The ‘Auto’ setting, on the other hand, will start the fan during a heating or cooling cycle and turn it off once the cycle is finished.

There are advantages and disadvantages to trying the fan setting on your thermostat, and what's ideal {will|can|should]] depend on your unique comfort needs.

Advantages to using the Fan/On setting:

  • You can keep the temperature in each room more consistent by allowing the fan to keep generating airflow.
  • Indoor air quality should improve since steady airflow will keep forcing airborne pollutants through the air filter.
  • Fewer start-stop cycles for the system's fan helps lengthen its life span. Since the air handler is often connected to the furnace, this means you can minimize the risk of needing furnace repair.

Downsides to using the Fan/On setting:

  • A nonstop fan can increase your energy expenses slightly.
  • Nonstop airflow may clog your air filter soon, increasing the frequency you’ll need to replace it.

{Choosing Between|Should My Thermostat Be on|Which Setting for My Thermostat? Fan or Auto in Summer/Winter

Through the summer, warm air will sometimes persist in unfinished spaces such as 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, compelling the HVAC system to run longer to keep up with the preferred temperature. In severe heat, this can lead to needing AC repair more often as wear and tear increases.

The opposite can occur in the winter. Cooler spaces like a basement will hold onto cooler air, which can eventually make its way into the rest of your home. Leaving the fan setting on will sometimes pull more cold air upward, increasing the amount of heating you need to keep warm.

If you’re still trying to decide if you should use the fan/on setting, don’t forget 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 other respiratory conditions can be tough on the family. Leaving the fan on can help to improve indoor air quality, helping your family breathe easier.

Your home deals with 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 should help limit these changes by constantly refreshing each room’s airflow.