When the weather starts to cool off, you are probably wondering about how you’ll take full advantage of your heating and cooling. After all, HVAC expenses can add up to a significant chunk of your monthly electric bill. To learn new ways to reduce costs, some people look closer at their thermostat. Could there be a setting they can use to improve efficiency?

Most thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a regular cycle, what will the fan setting provide for an HVAC system? This guide should help. We’ll review precisely what the fan setting is and whether 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 means that the system’s blower fan remains on. Certain furnaces can generate heat at a low level with this setting, but in general heating or cooling isn’t being generated. The ‘Auto’ setting, in contrast, will run the fan during a heating or cooling cycle and switch it off when the cycle is over.

There are advantages and disadvantages to using the fan setting on your thermostat, and what’s ideal {will|can|should]] depend on your unique comfort requirements.

Advantages to using the Fan/On setting:

  • You can keep the temperature throughout your home more balanced by allowing the fan to keep circulating air.
  • Indoor air quality will be highest as constant airflow will keep forcing airborne particles through the air filter.
  • A smaller amount of start-stop cycles for the HVAC fan helps lengthen its life span. As the air handler is typically a component of the furnace, this means you can avoid needing furnace repair.

Downsides to utilizing the Fan/On setting:

  • A nonstop fan will likely raise your energy expenses by a small margin.
  • Continuous airflow may clog your air filter soon, increasing the frequency you should replace it.

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

During the summer, warm air will sometimes stick around in unfinished spaces including 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 run longer to preserve the preferred temperature. In severe heat, this can lead to needing AC repair more often as wear and tear grows.

The opposite can take place over the winter. Cooler spaces like a basement will hold onto cooler air, which may eventually drift into the rest of your home. Leaving the fan setting on will sometimes pull 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 could work 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 deals with hot and cold spots. Many homes wrestle with stubborn hot and cold spots that quickly evolve to a temperature different from the rest of the house. The fan setting can help limit these changes by steadily refreshing each room’s airflow.