Once the weather is cooling off, you may be wondering about how you’ll take full advantage of your heating and cooling. After all, HVAC bills routinely contribute a significant portion of your monthly electric bill. To learn new ways to lower their HVAC bill, some homeowners take a closer look at their thermostat. Could there be 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 on during a typical cycle, what does the fan setting provide for the HVAC system? This guide should help. We’ll review precisely what the fan setting is and whether you can use it to reduce costs during the summer or winter.

What Is the Fan Setting on My Thermostat?

For the bulk of thermostats, the fan setting indicates that the system's blower fan remains on. A few furnaces will generate heat at a low level in this setting, but in most cases heating or cooling isn’t being generated. The ‘Auto’ setting, on the other hand, will turn on the fan through a heating or cooling cycle and switch it off after the cycle is finished.

There are pros and cons to switching on the fan setting on your thermostat, and what's ideal {will|can|should]] depend on your unique comfort requirements.

Advantages to switching to the Fan/On setting:

  • You can keep the temperature in every room more uniform by permitting the fan to keep circulating air.
  • Indoor air quality can increase as continuous airflow will keep passing airborne contaminants through the air filter.
  • A smaller number of start-stop cycles for the blower fan helps expand its life span. As the air handler is often a component of the furnace, this means you might prevent the need for furnace repair.

Downsides to utilizing the Fan/On setting:

  • A constant fan can increase your energy bills slightly.
  • Constant airflow may clog your air filter soon, increasing the frequency you’ll need to replace it.

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

Through the summer, warm air will sometimes persist in unfinished spaces such as the attic or an attached garage. If you use the fan setting, your HVAC system might draw this warm air into the rest of your home, pushing the HVAC system to work harder to maintain the desired temperature. In severe heat, this could lead to needing AC repair more often as wear and tear grows.

The reverse can happen during the winter. Cooler spaces such as a basement will hold onto cooler air, which may eventually make its way into the rest of your home. Leaving the fan running may draw 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 not the same. Leaving the HVAC system’s fan on might be ideal for you if:

Someone in your household has allergies. Allergies and similar respiratory conditions can be hard on the family. Leaving the fan on can help to improve indoor air quality, helping your family breathe easier.

Your home has hot and cold spots. Lots of homes deal with stubborn hot and cold spots that quickly shift to a temperature different from the rest of the house. The fan setting might help lessen these changes by consistently refreshing each room’s ventilation.