When the weather starts to cool off, you may be concerned about how you’ll take full advantage of your heating and cooling. After all, HVAC costs routinely contribute a significant piece of your monthly electric bill. To figure out new ways to lower their HVAC bill, some homeowners take a closer look at their thermostat. Is there a setting they can use to boost efficiency?

The bulk of thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a typical cycle, what does the fan setting offer for an HVAC system? This guide will help. We’ll share just what the fan setting is and whether you can use it to reduce costs in the summer or winter.

How Do I Access the Fan Setting on My Thermostat?

For the majority of thermostats, the fan setting means that the system's blower fan keeps running. Some furnaces will operate at a low level with this setting, but in general heating or cooling isn’t being produced. The ‘Auto’ setting, conversely, will run the fan during a heating or cooling cycle and shut it off once the cycle is complete.

There are advantages and disadvantages to using the fan setting on your thermostat, and the ideal option {will|can|should]] depend on your personal comfort preferences.

Advantages to switching to the Fan/On setting:

  • You can keep the temperature in each room more consistent by enabling the fan to keep running.
  • Indoor air quality can increase as constant airflow will keep passing airborne particles into the air filter.
  • A smaller amount of start-stop cycles for the HVAC fan helps expand its life span. As the air handler is often connected to the furnace, this means you can avoid needing furnace repair.

Downsides to using the Fan/On setting:

  • A continuous fan could add to your energy costs somewhat.
  • Continuous airflow could clog your air filter up more quickly, increasing the frequency you will want to 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 will sometimes persist in unfinished spaces like the attic or an attached garage. If you leave the fan on, your HVAC system can gradually move this warm air into the rest of your home, compelling the HVAC system to work harder to keep up with the desired temperature. In severe heat, this can lead to needing AC repair more often as wear and tear gets worse.

The opposite can happen over the winter. Cooler spaces like a basement will hold onto cooler air, which will eventually make its way into the rest of your home. Keeping the fan on could pump more cold air upward, increasing the amount of heating you need to keep 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 could work 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 should help to increase indoor air quality, helping your family breathe easier.

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