As the weather begins to cool off, you are probably wondering about how you’ll take full advantage of your heating and cooling. After all, HVAC expenses can add up to a big chunk of your monthly electric bill. To learn new ways to save, some homeowners look closer at their thermostat. Is there a setting they could use to boost efficiency?

The bulk of thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a normal cycle, what does the fan setting offer for your HVAC system? This guide should help. We’ll share precisely what the fan setting is and when you can use it to save money during the summer or winter.

What Is the Fan Setting on My Thermostat?

For the bulk of thermostats, the fan setting means that the air handler’s blower fan remains on. A few furnaces will generate heat at a low level with 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 switch it off when the cycle is complete.

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 unique comfort preferences.

Advantages to switching to the Fan/On setting:

  • You can keep the temperature in each room more uniform by allowing the fan to keep circulating air.
  • Indoor air quality will be highest because constant airflow will keep forcing airborne particles into the air filter.
  • A smaller amount of start-stop cycles for the system’s fan helps extend its life span. As the air handler is typically part of the furnace, this means you could minimize the risk of needing furnace repair.

Drawbacks to switching to the Fan/On setting:

  • A constant fan will likely increase your energy expenses slightly.
  • Constant airflow can clog your air filter in a shorter amount of time, increasing the frequency you will want to replace it.

Which Setting for My Thermostat? Fan or Auto in Each Season

Through the summer, warm air may stick around in unfinished spaces like the attic or an attached garage. If you keep the fan running, your HVAC system might draw this warm air into the rest of your home, forcing the HVAC system to work more to maintain the desired temperature. In serious heat, this can lead to needing AC repair more often as wear and tear grows.

The reverse can occur during the winter. Cooler spaces like a basement will hold onto cooler air, which may eventually flow into the rest of your home. Keeping the fan on may pump more cold air upward, increasing the amount of heating you need to keep warm.

If you’re still trying to decide if you should try the fan/on setting, remember that every home and family’s comfort needs will vary. Leaving the HVAC system’s fan on could be best for you if:

Someone in your household suffers from allergies. Allergies and other respiratory conditions can be tough on the family. Leaving the fan on can help to increase indoor air quality, helping your family breathe easier.

Your home deals with 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 should help limit these changes by steadily refreshing each room’s supply of air.