As the weather starts to cool off, you are probably thinking about how you’ll make the most of your heating and cooling. After all, HVAC bills routinely contribute a big piece of your monthly electric bill. To figure out new ways to save, some homeowners look closely at their thermostat. Could there be a setting they should use to boost efficiency?

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

What Is the Fan Setting on My Thermostat?

For the bulk of thermostats, the fan setting signifies that the HVAC blower fan stays on. A few furnaces may continue to operate at a low level with this setting, but in general heating or cooling isn’t being made. The ‘Auto’ setting, in contrast, will turn on the fan through a heating or cooling cycle and switch it off once the cycle is over.

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

Advantages to utilizing the Fan/On setting:

  • You can keep the temperature throughout your home more uniform by permitting the fan to keep running.
  • Indoor air quality can increase as constant airflow will keep forcing airborne particles into the air filter.
  • A smaller amount of start-stop cycles for the system's fan helps lengthen its life span. As the air handler is typically part of the furnace, this means you can avoid needing furnace repair.

Downsides to using the Fan/On setting:

  • A constant fan could add to your energy expenses somewhat.
  • Constant airflow may clog your air filter soon, increasing the frequency you will want to replace it.

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

During the summer, warm air will sometimes persist in unfinished spaces such as the attic or an attached garage. If you keep the fan running, your HVAC system can pull this warm air into the rest of your home, compelling the HVAC system to work more to maintain the set temperature. In extreme heat, this could result in needing AC repair more often as wear and tear gets worse.

The reverse can take place in the winter. Cooler spaces like a basement will hold onto cooler air, which can eventually flow into the rest of your home. Leaving the fan running will sometimes 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, remember that every home and family’s comfort needs are not the same. Leaving the HVAC system’s fan on might work for you if:

Someone in your household deals with allergies. Allergies and other respiratory conditions can be tough 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 wrestle with difficult hot and cold spots that quickly evolve to a temperature different from the rest of the house. The fan setting might help minimize these changes by constantly refreshing each room’s ventilation.