Once the weather begins to cool off, you may be thinking about how you’ll make the most of your heating and cooling. After all, HVAC expenses can make up a big portion of your monthly electric bill. To learn new ways to save, some owners take a closer look at their thermostat. Maybe there’s a setting they could use to improve efficiency?

The majority of thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a typical cycle, what does the fan setting offer for an HVAC system? This guide can help. We’ll walk through precisely what the fan setting is and how you can use it to reduce 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. A few furnaces may continue to run at a low level in this setting, but in most cases heating or cooling isn’t being produced. The ‘Auto’ setting, conversely, will run the fan through a heating or cooling cycle and shut it off once the cycle is complete.

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

Advantages to switching to the Fan/On setting:

  • You can keep the temperature throughout your home more uniform by allowing the fan to keep running.
  • Indoor air quality can increase because continuous airflow will keep forcing airborne contaminants into the air filter.
  • Fewer start-stop cycles for the system's fan helps lengthen its life span. Since the air handler is usually part of the furnace, this means you might minimize the risk of needing furnace repair.

Downsides to using the Fan/On setting:

  • A nonstop fan could raise your energy costs slightly.
  • Continuous airflow may clog your air filter in a shorter amount of time, increasing the frequency you’ll need to replace it.

{Choosing Between|Should My Thermostat Be on|Which Setting for My Thermostat? 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 leave the fan on, your HVAC system might gradually move this warm air into the rest of your home, pushing the HVAC system to work more to keep up with the preferred temperature. In extreme heat, this could result in needing AC repair more quickly as wear and tear gets worse.

The opposite can happen during the winter. Cooler spaces such as a basement will hold onto cooler air, which can eventually make its way into the rest of your home. Leaving the fan running may 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 switch to the fan/on setting, remember that every home and family’s comfort needs are different. Leaving the HVAC system’s fan on might work for you if:

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

Your home has hot and cold spots. All kinds of homes wrestle with persistent hot and cold spots that quickly shift to a temperature different from the rest of the house. The fan setting should help limit these changes by constantly refreshing each room’s supply of air.