As the weather begins to cool off, you are probably thinking about how you’ll prepare your heating and cooling. After all, HVAC bills routinely contribute a large chunk of your monthly electric bill. To try and find ways to save, some homeowners look closer at their thermostat. Could there be a setting they should use to improve efficiency?

Most thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a typical cycle, what will the fan setting offer for the HVAC system? This guide should help. We’ll walk through precisely what the fan setting is and how you can use it to cut costs during the summer or winter.

Should I Use My Thermostat’s Fan Setting?

For the majority of thermostats, the fan setting signifies that the system’s blower fan keeps running. Certain furnaces can run at a low level with this setting, but for the most part heating or cooling isn’t being generated. The ‘Auto’ setting, on the other hand, will turn on the fan over a heating or cooling cycle and switch it off when the cycle is over.

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

Advantages to switching to the Fan/On setting:

  • You can keep the temperature in each room more balanced by allowing the fan to keep running.
  • Indoor air quality should improve because constant airflow will keep forcing airborne pollutants into the air filter.
  • Fewer start-stop cycles for the blower fan helps lengthen its life span. As the air handler is usually a component of the furnace, this means you could avoid needing furnace repair.

Downsides to using the Fan/On setting:

  • A constant fan could add to your energy bills by a small margin.
  • Constant airflow may clog your air filter up more quickly, increasing the frequency you will want to replace it.

{Choosing Between|Should My Thermostat Be on|Which Setting for My Thermostat? Fan or Auto in Summer/Winter

In the summer, warm air may persist in unfinished spaces such as the attic or an attached garage. If you keep the fan running, your HVAC system may gradually move this warm air into the rest of your home, forcing the HVAC system to work more to preserve the set temperature. In serious heat, this could lead to needing AC repair more quickly as wear and tear gets worse.

The opposite can happen over the winter. Cooler spaces like a basement will hold onto cooler air, which can eventually make its way into the rest of your home. Leaving the fan running will sometimes draw more cold air upward, increasing the amount of heating you need to remain warm.

If you’re still trying to decide if you should use 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 could be ideal for you if:

Someone in your household deals with allergies. Allergies and other respiratory conditions can be tough on the family. Leaving the fan on is more likely to improve indoor air quality, helping your family breathe easier.

Your home experiences hot and cold spots. Lots of 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 limit these changes by steadily refreshing each room’s supply of air.