As the weather starts to cool off, you might be concerned about how you’ll take full advantage of your heating and cooling. After all, HVAC expenses can add up to a large chunk of your monthly electric bill. To figure out new ways to lower their HVAC bill, some people look closer at their thermostat. Maybe there’s a setting they should use to increase efficiency?

The majority of thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a regular cycle, what can the fan setting offer for an HVAC system? This guide can help. We’ll walk through just what the fan setting is and when you can use it to cut costs in the summer or winter.

How Do I Access the Fan Setting on My Thermostat?

For most thermostats, the fan setting signifies that the air handler’s blower fan keeps running. A few furnaces may continue to run at a low level in this setting, but in most cases heating or cooling isn’t being made. The ‘Auto’ setting, in contrast, will start the fan through a heating or cooling cycle and turn it off when the cycle is finished.

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

Advantages to trying the Fan/On setting:

  • You can keep the temperature in every room more balanced by allowing the fan to keep circulating air.
  • Indoor air quality can increase because steady airflow will keep moving airborne particles into the air filter.
  • A smaller amount of start-stop cycles for the HVAC fan helps expand its life span. Since the air handler is often connected to the furnace, this means you might avoid needing furnace repair.

Drawbacks to switching to the Fan/On setting:

  • A continuous fan will likely raise your energy bills somewhat.
  • Continuous airflow can 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 leave the fan on, your HVAC system can draw this warm air into the rest of your home, compelling the HVAC system to run longer to maintain the set temperature. In serious heat, this can result in needing AC repair more regularly as wear and tear grows.

The opposite can happen during the winter. Cooler spaces such as a basement will hold onto cooler air, which can eventually flow 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 decide if you should try the fan/on setting, don’t forget that every home and family’s comfort needs are different. Leaving the HVAC system’s fan on could be best for you if:

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

Your home has hot and cold spots. Lots of homes wrestle with difficult 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 airflow.