Once the weather begins to cool off, you are probably wondering about how you’ll make the most of your heating and cooling. After all, HVAC bills routinely make up a big chunk of your monthly electric bill. To learn new ways to reduce costs, some homeowners look closely at their thermostat. Maybe there’s a setting they can use to boost efficiency?

The majority of thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a typical cycle, what will the fan setting provide for your HVAC system? This guide will help. We’ll share what exactly the fan setting is and when you can use it to save money during the summer or winter.

Should I Use My Thermostat's Fan Setting?

For most thermostats, the fan setting signifies that the air handler’s blower fan stays on. Certain furnaces may continue to generate heat at a low level in this setting, but for the most part heating or cooling isn’t being generated. The ‘Auto’ setting, conversely, will turn on the fan through a heating or cooling cycle and turn it off once the cycle is finished.

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

Advantages to switching to the Fan/On setting:

  • You can keep the temperature in each room more balanced by permitting the fan to keep generating airflow.
  • Indoor air quality will be highest because constant airflow will keep passing airborne contaminants through the air filter.
  • A smaller number of start-stop cycles for the blower fan helps extend its life span. As the air handler is usually part of the furnace, this means you can avoid needing furnace repair.

Drawbacks to using the Fan/On setting:

  • A constant fan will likely add to your energy bills by a small margin.
  • Nonstop airflow can clog your air filter soon, 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

In the summer, warm air may linger in unfinished spaces such as 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, forcing the HVAC system to work more to keep up with the preferred temperature. In extreme heat, this can result in needing AC repair more quickly as wear and tear grows.

The reverse can occur over the winter. Cooler spaces such as a basement will hold onto cooler air, which can eventually make its way 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 stay warm.

If you’re still trying to decide if you should try 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 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 should help to enhance indoor air quality, helping your family breathe easier.

Your home deals with hot and cold spots. Lots of homes deal with persistent hot and cold spots that quickly evolve to a temperature different from the rest of the house. The fan setting can help limit these changes by constantly refreshing each room’s supply of air.