As the weather begins to cool off, you might be concerned about how you’ll take full advantage of your heating and cooling. After all, HVAC bills can add up to a significant chunk of your monthly electric bill. To try and find ways to reduce costs, some homeowners take a closer look at their thermostat. Is there a setting they can use to improve efficiency?

The bulk of thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a regular cycle, what can the fan setting provide for your HVAC system? This guide can help. We’ll walk through just what the fan setting is and when you can use it to reduce costs during the summer or winter.

My Thermostat Has a Fan Setting?

For the bulk of thermostats, the fan setting signifies that the HVAC blower fan remains on. Some furnaces can generate heat at a low level with this setting, but for the most part heating or cooling isn’t being generated. The ‘Auto’ setting, in contrast, will start the fan during a heating or cooling cycle and turn it off after the cycle is over.

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

Advantages to using the Fan/On setting:

  • You can keep the temperature in each room more uniform by enabling the fan to keep generating airflow.
  • Indoor air quality will be highest since constant airflow will keep passing airborne contaminants through the air filter.
  • A smaller number of start-stop cycles for the blower fan helps expand its life span. As the air handler is often a component of the furnace, this means you might minimize the risk of needing furnace repair.

Downsides to using the Fan/On setting:

  • A continuous fan could raise your energy bills slightly.
  • Continuous airflow could 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 Summer/Winter

Through the summer, warm air may linger in unfinished spaces including the attic or an attached garage. If you keep the fan running, your HVAC system can gradually move this warm air into the rest of your home, forcing the HVAC system to work harder to keep up with the desired temperature. In severe heat, this may lead to needing AC repair more quickly as wear and tear increases.

The reverse can happen during the winter. Cooler spaces such as a basement will hold onto cooler air, which will eventually drift 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 decide 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 might work for you if:

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

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