Once the weather starts to cool off, you are probably concerned about how you’ll prepare your heating and cooling. After all, HVAC costs routinely add up to a significant chunk of your monthly electric bill. To figure out new ways to save, some owners look closer at their thermostat. Is there a setting they could use to boost efficiency?

Most thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a regular cycle, what will the fan setting provide for the HVAC system? This guide can help. We’ll review what exactly the fan setting is and whether you can use it to cut costs during the summer or winter.

What Is the Fan Setting on My Thermostat?

For the majority of thermostats, the fan setting means that the HVAC blower fan stays on. A few furnaces will operate at a low level in this setting, but in general heating or cooling isn’t being generated. The ‘Auto’ setting, conversely, will start the fan over a heating or cooling cycle and shut it off when the cycle is complete.

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 unique comfort needs.

Advantages to switching to the Fan/On setting:

  • You can keep the temperature throughout your home more uniform by enabling the fan to keep generating airflow.
  • Indoor air quality will be highest because constant airflow will keep passing airborne pollutants through the air filter.
  • A smaller number of start-stop cycles for the blower fan helps extend its life span. Because the air handler is often a component of the furnace, this means you can avoid needing furnace repair.

Downsides to switching to the Fan/On setting:

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

Should My Thermostat Be on Fan or Auto in Summer/Winter

In the summer, warm air can linger in unfinished spaces like the attic or an attached garage. If you leave the fan on, your HVAC system may draw this warm air into the rest of your home, forcing the HVAC system to work more to maintain the desired temperature. In extreme heat, this may lead to needing AC repair more quickly as wear and tear increases.

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

If you’re still trying to determine if you should use the fan/on setting, keep in mind 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 similar respiratory conditions can be stressful on the family. Leaving the fan on should help to increase indoor air quality, helping your family breathe easier.

Your home deals with hot and cold spots. All kinds of homes deal with difficult hot and cold spots that quickly return to a temperature different from the rest of the house. The fan setting might help minimize these changes by constantly refreshing each room’s airflow.