Once the weather starts to cool off, you may be thinking about how you’ll prepare your heating and cooling. After all, HVAC costs can contribute a large chunk of your monthly electric bill. To figure out new ways to reduce costs, some homeowners look closely at their thermostat. Is there a setting they should use to boost efficiency?

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

Should I Use My Thermostat's Fan Setting?

For most thermostats, the fan setting means that the air handler’s blower fan stays on. A few furnaces can operate at a low level with this setting, but in general heating or cooling isn’t being generated. The ‘Auto’ setting, in contrast, will turn on the fan through a heating or cooling cycle and turn it off once the cycle is complete.

There are advantages and disadvantages to trying the fan setting on your thermostat, and the ideal option {will|can|should]] depend on your unique 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 generating airflow.
  • Indoor air quality can increase because constant airflow will keep passing airborne particles into the air filter.
  • A smaller number of start-stop cycles for the system's fan helps extend its life span. As the air handler is often connected to the furnace, this means you could avoid needing furnace repair.

Disadvantages to utilizing the Fan/On setting:

  • A constant fan will likely add to your energy bills by a small margin.
  • Continuous airflow may clog your air filter in a shorter amount of time, 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 stick around in unfinished spaces including the attic or an attached garage. If you leave the fan on, your HVAC system may gradually move this warm air into the rest of your home, pushing the HVAC system to work harder to preserve the preferred temperature. In extreme heat, this may result in needing AC repair more often as wear and tear grows.

The reverse can happen during the winter. Cooler spaces such as a basement will hold onto cooler air, which can eventually make its way into the rest of your home. Leaving the fan running 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, don’t forget that every home and family’s comfort needs are different. Leaving the HVAC system’s fan on may be best for you if:

Someone in your household deals with allergies. Allergies and similar respiratory conditions can be tough on the family. Leaving the fan on can help to enhance indoor air quality, helping your family breathe easier.

Your home experiences hot and cold spots. All kinds of homes deal with stubborn hot and cold spots that quickly evolve to a temperature different from the rest of the house. The fan setting can help minimize these changes by steadily refreshing each room’s ventilation.