Once the weather starts to cool off, you might be thinking about how you’ll take full advantage of your heating and cooling. After all, HVAC bills frequently contribute a large piece of your monthly electric bill. To learn new ways to reduce costs, some homeowners look closer at their thermostat. Maybe there’s a setting they can use to increase efficiency?

The majority of thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a typical cycle, what can the fan setting provide for an HVAC system? This guide will help. We’ll walk through what exactly the fan setting is and how you can use it to reduce costs over the summer or winter.

Should I Use My Thermostat’s Fan Setting?

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 in this setting, but for the most part heating or cooling isn’t being made. The ‘Auto’ setting, conversely, will start the fan through a heating or cooling cycle and shut it off after the cycle is complete.

There are advantages and disadvantages to switching on the fan setting on your thermostat, and whether you do or don’t {will|can|should]] depend on your unique comfort needs.

Advantages to using the Fan/On setting:

  • You can keep the temperature in every room more uniform by permitting the fan to keep running.
  • Indoor air quality should improve because constant airflow will keep moving airborne particles through the air filter.
  • A smaller amount of start-stop cycles for the HVAC fan helps lengthen its life span. Since the air handler is usually part of the furnace, this means you can prevent the need for furnace repair.

Disadvantages to using the Fan/On setting:

  • A nonstop fan could increase your energy bills somewhat.
  • Nonstop airflow may clog your air filter in a shorter amount of time, 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 Each Season

In the summer, warm air may linger in unfinished spaces including the attic or an attached garage. If you keep the fan running, your HVAC system might gradually move this warm air into the rest of your home, forcing the HVAC system to run longer to keep up with the set temperature. In extreme heat, this can lead to needing AC repair more regularly as wear and tear increases.

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

If you’re still trying to decide 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 might be best for you if:

Someone in your household has allergies. Allergies and similar respiratory conditions can be stressful on the family. Leaving the fan on can help to improve 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 limit these changes by consistently refreshing each room’s airflow.