When the weather is cooling off, you might be concerned about how you’ll make the most of your heating and cooling. After all, HVAC expenses frequently contribute a large portion of your monthly electric bill. To figure out new ways to save, some owners take a closer look at their thermostat. Maybe there’s a setting they should use to improve efficiency?

The bulk of thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a regular cycle, what does the fan setting offer for an HVAC system? This guide can help. We’ll walk through just what the fan setting is and when you can use it to cut costs during the summer or winter.

How Do I Access the Fan Setting on My Thermostat?

For the majority of thermostats, the fan setting means that the air handler’s blower fan keeps running. Some furnaces may continue to operate at a low level with this setting, but for the most part heating or cooling isn’t being generated. The ‘Auto’ setting, conversely, will turn on the fan through a heating or cooling cycle and switch it off after the cycle is over.

There are pros and cons to using the fan setting on your thermostat, and the ideal option {will|can|should]] depend on your unique comfort needs.

Advantages to switching to the Fan/On setting:

  • You can keep the temperature in each room more consistent by allowing the fan to keep running.
  • Indoor air quality can increase as constant airflow will keep passing airborne particles through the air filter.
  • Fewer start-stop cycles for the blower fan helps expand its life span. Since the air handler is usually part of the furnace, this means you could prevent the need for furnace repair.

Drawbacks to utilizing the Fan/On setting:

  • A continuous fan will likely increase your energy bills by a small margin.
  • Nonstop airflow could clog your air filter soon, increasing the frequency you should replace it.

Should My Thermostat Be on? Fan or Auto in Each Season

Through the summer, warm air will sometimes stick around in unfinished spaces such as the attic or an attached garage. If you use the fan setting, your HVAC system might draw this warm air into the rest of your home, forcing the HVAC system to run longer to preserve the desired temperature. In serious heat, this can lead to needing AC repair more often as wear and tear gets worse.

The opposite can take place in the winter. Cooler spaces such as a basement will hold onto cooler air, which will eventually make its way into the rest of your home. Keeping the fan on could pull more cold air upward, increasing the amount of heating you need to keep warm.

If you’re still trying to figure out if you should try the fan/on setting, keep in mind that every home and family’s comfort needs are not the same. Leaving the HVAC system’s fan on may work for you if:

Someone in your household deals with allergies. Allergies and similar respiratory conditions can be hard 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. All kinds of homes deal with stubborn hot and cold spots that quickly return to a temperature different from the rest of the house. The fan setting can help minimize these changes by consistently refreshing each room’s supply of air.