As the weather starts to cool off, you might be wondering about how you’ll make the most of your heating and cooling. After all, HVAC bills routinely make up a large portion of your monthly electric bill. To figure out new ways to save, some people look closer at their thermostat. Is there a setting they can use to improve efficiency?

Most thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a normal cycle, what does the fan setting offer for an HVAC system? This guide should help. We’ll share precisely what the fan setting is and how you can use it to reduce costs over the summer or winter.

What Is the Fan Setting on My Thermostat?

For most thermostats, the fan setting indicates that the air handler’s blower fan remains on. Some furnaces will operate at a low level with this setting, but in most cases heating or cooling isn’t being generated. The ‘Auto’ setting, in contrast, will run the fan over a heating or cooling cycle and switch it off when the cycle is finished.

There are benefits and drawbacks 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 switching to the Fan/On setting:

  • You can keep the temperature in every room more consistent by permitting the fan to keep running.
  • Indoor air quality can increase since constant airflow will keep forcing airborne pollutants through the air filter.
  • A smaller number of start-stop cycles for the blower fan helps expand its life span. Because the air handler is typically a component of the furnace, this means you could prevent the need for furnace repair.

Disadvantages to switching to the Fan/On setting:

  • A nonstop fan can increase your energy costs somewhat.
  • Constant airflow could clog your air filter soon, increasing the frequency you’ll need to replace it.

{Choosing Between|Should My Thermostat Be on|Which Setting for My Thermostat? Fan or Auto in Each Season

During the summer, warm air will sometimes linger in unfinished spaces such as the attic or an attached garage. If you use the fan setting, your HVAC system may draw this warm air into the rest of your home, forcing the HVAC system to work harder to preserve the preferred temperature. In serious heat, this could result in needing AC repair more often as wear and tear gets worse.

The opposite can happen in the winter. Cooler spaces such as a basement will hold onto cooler air, which will eventually make its way into the rest of your home. Leaving the fan setting on may draw more cold air upward, increasing the amount of heating you need to remain warm.

If you’re still trying to figure out if you should try 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 may work for you if:

Someone in your household deals with allergies. Allergies and similar respiratory conditions can be stressful on the family. Leaving the fan on is more likely to increase indoor air quality, helping your family breathe easier.

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