Once the weather starts to cool off, you may be wondering about how you’ll take full advantage of your heating and cooling. After all, HVAC expenses routinely contribute a significant portion of your monthly electric bill. To learn new ways to reduce costs, some people look closer at their thermostat. Maybe there’s a setting they could use to improve efficiency?

Most thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a regular cycle, what can the fan setting provide for the HVAC system? This guide should help. We’ll share just what the fan setting is and whether you can use it to reduce costs over the summer or winter.

My Thermostat Has a Fan Setting?

For the bulk of thermostats, the fan setting signifies that the system's blower fan keeps running. A few furnaces may continue to operate at a low level in this setting, but for the most part heating or cooling isn’t being generated. The ‘Auto’ setting, on the other hand, will run the fan over a heating or cooling cycle and shut 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 unique comfort preferences.

Advantages to utilizing the Fan/On setting:

  • You can keep the temperature in every room more uniform by enabling the fan to keep running.
  • Indoor air quality should improve because steady airflow will keep passing airborne contaminants into the air filter.
  • A smaller number of start-stop cycles for the blower fan helps expand its life span. Since the air handler is usually a component of the furnace, this means you might prevent the need for furnace repair.

Disadvantages to using the Fan/On setting:

  • A constant fan could increase your energy costs somewhat.
  • Continuous airflow may clog your air filter up more quickly, 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 may linger in unfinished spaces including the attic or an attached garage. If you use the fan setting, your HVAC system can pull this warm air into the rest of your home, forcing the HVAC system to run longer to keep up with the set temperature. In severe heat, this could result in needing AC repair more often as wear and tear grows.

The opposite can take place over the winter. Cooler spaces such as a basement will hold onto cooler air, which may eventually flow 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 figure out if you should switch to the fan/on setting, don’t forget that every home and family’s comfort needs are not the same. Leaving the HVAC system’s fan on could work for you if:

Someone in your household has allergies. Allergies and similar respiratory conditions can be hard on the family. Leaving the fan on should help to increase indoor air quality, helping your family breathe easier.

Your home experiences hot and cold spots. All kinds of homes wrestle with stubborn hot and cold spots that quickly return to a temperature different from the rest of the house. The fan setting should help minimize these changes by consistently refreshing each room’s airflow.