As the weather begins to cool off, you might be thinking about how you’ll prepare your heating and cooling. After all, HVAC costs can add up to a large portion of your monthly electric bill. To figure out new ways to save, some owners look closely at their thermostat. Is there a setting they could use to improve efficiency?

The majority 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 provide for an HVAC system? This guide should help. We’ll walk through what exactly the fan setting is and whether you can use it to cut costs in the summer or winter.

What Is the Fan Setting on My Thermostat?

For the bulk of thermostats, the fan setting indicates that the HVAC blower fan keeps running. Certain furnaces may continue to run at a low level in this setting, but for the most part heating or cooling isn’t being made. The ‘Auto’ setting, in contrast, will run the fan through a heating or cooling cycle and switch it off once the cycle is complete.

There are pros and cons to switching on the fan setting on your thermostat, and whether you do or don’t {will|can|should]] depend on your unique comfort requirements.

Advantages to utilizing the Fan/On setting:

  • You can keep the temperature in each room more balanced by allowing the fan to keep circulating air.
  • Indoor air quality can increase as continuous airflow will keep passing airborne pollutants through the air filter.
  • A smaller number of start-stop cycles for the HVAC fan helps extend its life span. Because the air handler is often a component of the furnace, this means you could minimize the risk of needing furnace repair.

Disadvantages to using the Fan/On setting:

  • A constant fan can add to your energy bills somewhat.
  • Continuous airflow can 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

Through the summer, warm air may persist in unfinished spaces such as the attic or an attached garage. If you leave the fan on, your HVAC system might pull this warm air into the rest of your home, forcing the HVAC system to work more to keep up with the preferred temperature. In severe heat, this may result in needing AC repair more regularly as wear and tear grows.

The opposite can occur in the winter. Cooler spaces like a basement will hold onto cooler air, which will eventually flow into the rest of your home. Leaving the fan running will sometimes pump more cold air upward, increasing the amount of heating you need to keep warm.

If you’re still trying to figure out if you should switch to the fan/on setting, keep in mind that every home and family’s comfort needs are not the same. Leaving the HVAC system’s fan on could work for you if:

Someone in your household suffers from 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 persistent hot and cold spots that quickly shift to a temperature different from the rest of the house. The fan setting should help minimize these changes by constantly refreshing each room’s airflow.