When the weather begins to cool off, you might be thinking about how you’ll make the most of your heating and cooling. After all, HVAC costs can make up a significant chunk of your monthly electric bill. To learn new ways to lower their HVAC bill, some owners look closely at their thermostat. Maybe there’s a setting they should use to boost efficiency?

Most thermostats have 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 will help. We’ll review just what the fan setting is and whether you can use it to reduce costs during the summer or winter.

My Thermostat Has a Fan Setting?

For the bulk of thermostats, the fan setting means that the air handler’s blower fan stays on. Certain furnaces can generate heat at a low level with this setting, but for the most part heating or cooling isn’t being produced. The ‘Auto’ setting, in contrast, will run the fan during a heating or cooling cycle and shut it off once the cycle is finished.

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

Advantages to switching to the Fan/On setting:

  • You can keep the temperature in each room more uniform by permitting the fan to keep generating airflow.
  • Indoor air quality should improve because steady airflow will keep forcing airborne contaminants through the air filter.
  • Fewer start-stop cycles for the blower fan helps extend its life span. Since the air handler is typically connected to the furnace, this means you can prevent the need for furnace repair.

Downsides to utilizing the Fan/On setting:

  • A continuous fan could add to your energy bills by a small margin.
  • Continuous airflow may clog your air filter soon, increasing the frequency you should 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 persist in unfinished spaces such as the attic or an attached garage. If you use the fan setting, your HVAC system may draw this warm air into the rest of your home, compelling the HVAC system to work more to maintain the preferred temperature. In serious heat, this can lead to needing AC repair more often as wear and tear grows.

The opposite can occur 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 running will sometimes pull more cold air upward, increasing the amount of heating you need to remain 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 will vary. 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 tough on the family. Leaving the fan on can help to improve indoor air quality, helping your family breathe easier.

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