As the weather starts to cool off, you might be thinking about how you’ll make the most of your heating and cooling. After all, HVAC costs routinely contribute a big portion of your monthly electric bill. To figure out new ways to save, some owners look closer at their thermostat. Could there be a setting they can use to increase efficiency?

The bulk of thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a typical cycle, what will the fan setting offer for the HVAC system? This guide can help. We’ll review precisely what the fan setting is and how you can use it to save money over the summer or winter.

My Thermostat Has a Fan Setting?

For the bulk of thermostats, the fan setting means that the air handler’s blower fan remains on. Certain furnaces can run at a low level with this setting, but for the most part heating or cooling isn’t being made. The ‘Auto’ setting, in contrast, will turn on the fan through a heating or cooling cycle and switch it off once the cycle is over.

There are benefits and drawbacks 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 throughout your home more uniform by allowing the fan to keep running.
  • Indoor air quality should improve because continuous airflow will keep forcing airborne contaminants into 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 often connected to the furnace, this means you could prevent the need for furnace repair.

Drawbacks to switching to the Fan/On setting:

  • A constant fan could raise your energy bills by a small margin.
  • Constant airflow can 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 Summer/Winter

In the summer, warm air can linger in unfinished spaces like the attic or an attached garage. If you use the fan setting, your HVAC system may pull this warm air into the rest of your home, compelling the HVAC system to run longer to maintain the set temperature. In extreme heat, this could result in needing AC repair more often as wear and tear increases.

The reverse can occur in the winter. Cooler spaces such as a basement will hold onto cooler air, which can eventually flow into the rest of your home. Keeping the fan on could draw more cold air upward, increasing the amount of heating you need to stay warm.

If you’re still trying to determine if you should switch to the fan/on setting, don’t forget that every home and family’s comfort needs will vary. Leaving the HVAC system’s fan on might be best 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 improve indoor air quality, helping your family breathe easier.

Your home experiences hot and cold spots. Many 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 consistently refreshing each room’s airflow.