Once the weather is cooling off, you may be thinking about how you’ll take full advantage of your heating and cooling. After all, HVAC costs can make up a large piece of your monthly electric bill. To try and find ways to lower their HVAC bill, some homeowners look closely at their thermostat. Maybe there’s a setting they could use to boost efficiency?

The bulk of thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a typical cycle, what does the fan setting provide for an HVAC system? This guide should help. We’ll review precisely what the fan setting is and how you can use it to reduce costs in the summer or winter.

What Is the Fan Setting on My Thermostat?

For the bulk of thermostats, the fan setting signifies that the air handler’s blower fan remains on. Some furnaces may continue to run at a low level with this setting, but for the most part heating or cooling isn’t being made. The ‘Auto’ setting, on the other hand, will run the fan over a heating or cooling cycle and turn it off once the cycle is finished.

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

Advantages to trying the Fan/On setting:

  • You can keep the temperature in every room more consistent by enabling the fan to keep running.
  • Indoor air quality can increase since steady airflow will keep moving airborne contaminants into the air filter.
  • Fewer start-stop cycles for the blower fan helps expand its life span. As the air handler is typically part of the furnace, this means you can prevent the need for furnace repair.

Downsides to using the Fan/On setting:

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

Through the summer, warm air can linger 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 run longer to maintain the preferred temperature. In extreme heat, this can result in needing AC repair more quickly as wear and tear increases.

The reverse can happen over the winter. Cooler spaces like a basement will hold onto cooler air, which may eventually make its way into the rest of your home. Keeping the fan on could pull more cold air upward, increasing the amount of heating you need to remain 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 will vary. Leaving the HVAC system’s fan on might be best for you if:

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

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