As the weather is cooling off, you might be wondering about how you’ll take full advantage of your heating and cooling. After all, HVAC costs frequently make up a big portion of your monthly electric bill. To figure out new ways to save, some owners take a closer look at their thermostat. Could there be a setting they should use to increase efficiency?

The majority of thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a typical cycle, what does the fan setting provide for the HVAC system? This guide can help. We’ll share what exactly the fan setting is and how you can use it to cut costs in the summer or winter.

What Is the Fan Setting on My Thermostat?

For the majority of thermostats, the fan setting indicates that the system's blower fan stays on. Some furnaces may continue to operate at a low level with this setting, but in general heating or cooling isn’t being made. The ‘Auto’ setting, conversely, will start the fan during a heating or cooling cycle and turn it off once the cycle is complete.

There are advantages and disadvantages to switching on the fan setting on your thermostat, and whether you do or don’t {will|can|should]] depend on your distinct comfort preferences.

Advantages to using the Fan/On setting:

  • You can keep the temperature in every room more consistent by allowing the fan to keep running.
  • Indoor air quality will be highest since steady airflow will keep passing airborne particles into the air filter.
  • Fewer start-stop cycles for the blower fan helps lengthen its life span. Because the air handler is typically a component of the furnace, this means you can avoid needing furnace repair.

Drawbacks to switching to the Fan/On setting:

  • A nonstop fan can increase your energy costs somewhat.
  • Constant airflow could 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

During 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, pushing the HVAC system to work harder to preserve the preferred temperature. In serious heat, this can result in needing AC repair more quickly as wear and tear gets worse.

The opposite can occur over the winter. Cooler spaces like a basement will hold onto cooler air, which can eventually flow 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 decide if you should use the fan/on setting, remember that every home and family’s comfort needs are not the same. Leaving the HVAC system’s fan on might work for you if:

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

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