When the weather is cooling off, you are probably thinking about how you’ll make the most of your heating and cooling. After all, HVAC costs frequently contribute a big portion of your monthly electric bill. To try and find ways to save, some owners take a closer look at their thermostat. Is there a setting they should use to increase efficiency?

The bulk of thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a regular cycle, what will the fan setting offer for your HVAC system? This guide should help. We’ll walk through 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 majority of thermostats, the fan setting means that the air handler’s blower fan keeps running. Certain furnaces can generate heat at a low level with this setting, but in most cases heating or cooling isn’t being made. The ‘Auto’ setting, on the other hand, will turn on the fan through a heating or cooling cycle and shut it off after the cycle is complete.

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

Advantages to utilizing the Fan/On setting:

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

Drawbacks to using the Fan/On setting:

  • A constant fan will likely add to your energy costs by a small margin.
  • Nonstop airflow can 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

During the summer, warm air can stick around in unfinished spaces like the attic or an attached garage. If you use the fan setting, your HVAC system might gradually move this warm air into the rest of your home, compelling the HVAC system to work harder to maintain the preferred temperature. In extreme heat, this may result in needing AC repair more regularly as wear and tear grows.

The reverse can occur during the winter. Cooler spaces like a basement will hold onto cooler air, which can eventually drift into the rest of your home. Leaving the fan running could 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 use the fan/on setting, don’t forget that every home and family’s comfort needs will vary. Leaving the HVAC system’s fan on could be best for you if:

Someone in your household suffers from allergies. Allergies and similar respiratory conditions can be tough on the family. Leaving the fan on can help to enhance indoor air quality, helping your family breathe easier.

Your home deals with hot and cold spots. Many homes deal with stubborn hot and cold spots that quickly evolve to a temperature different from the rest of the house. The fan setting can help minimize these changes by steadily refreshing each room’s supply of air.