Once the weather is cooling off, you may be concerned about how you’ll make the most of your heating and cooling. After all, HVAC bills frequently add up to a significant chunk of your monthly electric bill. To figure out new ways to save, some homeowners look closely at their thermostat. Maybe there’s a setting they can use to increase efficiency?

The bulk of thermostats include both 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 walk through precisely what the fan setting is and how you can use it to reduce costs in the summer or winter.

What Is the Fan Setting on My Thermostat?

For the majority of thermostats, the fan setting signifies that the HVAC blower fan remains on. Certain furnaces may continue to operate at a low level in this setting, but in most cases heating or cooling isn’t being generated. The ‘Auto’ setting, in contrast, will start the fan over a heating or cooling cycle and switch it off when the cycle is over.

There are benefits and drawbacks to trying the fan setting on your thermostat, and whether you do or don’t {will|can|should]] depend on your distinct comfort preferences.

Advantages to using the Fan/On setting:

  • You can keep the temperature in each room more consistent by permitting the fan to keep circulating air.
  • Indoor air quality will be highest as steady airflow will keep forcing airborne pollutants into the air filter.
  • A smaller number of start-stop cycles for the HVAC fan helps expand its life span. Since the air handler is often connected to the furnace, this means you can minimize the risk of needing furnace repair.

Disadvantages to using the Fan/On setting:

  • A nonstop fan can increase your energy costs somewhat.
  • Constant airflow can clog your air filter in a shorter amount of time, 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 may persist in unfinished spaces like the attic or an attached garage. If you keep the fan running, your HVAC system might gradually move this warm air into the rest of your home, forcing the HVAC system to work more to preserve the set temperature. In severe heat, this can lead to needing AC repair more often as wear and tear increases.

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

If you’re still trying to figure out if you should switch to the fan/on setting, keep in mind that every home and family’s comfort needs will vary. Leaving the HVAC system’s fan on may be best for you if:

Someone in your household suffers from allergies. Allergies and other respiratory conditions can be stressful on the family. Leaving the fan on is more likely to enhance indoor air quality, helping your family breathe easier.

Your home has hot and cold spots. All kinds 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 should help limit these changes by consistently refreshing each room’s supply of air.