When the weather is cooling off, you may be concerned about how you’ll take full advantage of your heating and cooling. After all, HVAC expenses can make up a significant portion of your monthly electric bill. To figure out new ways to reduce costs, some people look closely at their thermostat. Is there a setting they could use to increase efficiency?

The bulk of thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a typical cycle, what does the fan setting provide for an HVAC system? This guide can help. We’ll review what exactly the fan setting is and how you can use it to cut 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 system's blower fan stays on. Certain furnaces can operate at a low level with this setting, but in most cases heating or cooling isn’t being produced. The ‘Auto’ setting, conversely, will turn on the fan during a heating or cooling cycle and switch it off when the cycle is finished.

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 preferences.

Advantages to utilizing the Fan/On setting:

  • You can keep the temperature in each room more uniform by allowing the fan to keep running.
  • Indoor air quality can increase since constant airflow will keep forcing airborne pollutants through the air filter.
  • A smaller number of start-stop cycles for the HVAC fan helps extend its life span. Because the air handler is often a component of the furnace, this means you could avoid needing furnace repair.

Drawbacks to switching to the Fan/On setting:

  • A constant fan could raise your energy bills by a small margin.
  • Constant airflow could 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 may stick around in unfinished spaces like the attic or an attached garage. If you use the fan setting, your HVAC system can gradually move this warm air into the rest of your home, pushing the HVAC system to run longer to preserve the desired temperature. In extreme heat, this may result in needing AC repair more quickly as wear and tear increases.

The reverse can take place during the winter. Cooler spaces such as a basement will hold onto cooler air, which can eventually flow into the rest of your home. Leaving the fan setting on may pump 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, remember 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 deals with allergies. Allergies and other respiratory conditions can be stressful on the family. Leaving the fan on can help to increase indoor air quality, helping your family breathe easier.

Your home experiences hot and cold spots. Many homes wrestle with persistent hot and cold spots that quickly evolve to a temperature different from the rest of the house. The fan setting should help lessen these changes by steadily refreshing each room’s supply of air.