Once the weather starts to cool off, you are probably thinking about how you’ll make the most of your heating and cooling. After all, HVAC expenses routinely make up a significant portion of your monthly electric bill. To try and find ways to lower their HVAC bill, some people look closer at their thermostat. Could there be a setting they could use to increase efficiency?

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

Should I Use My Thermostat’s Fan Setting?

For most thermostats, the fan setting indicates that the system’s blower fan remains on. A few furnaces can run at a low level in this setting, but in most cases heating or cooling isn’t being produced. The ‘Auto’ setting, in contrast, will start the fan over a heating or cooling cycle and turn it off after the cycle is finished.

There are pros and cons to trying the fan setting on your thermostat, and whether you do or don’t {will|can|should]] depend on your distinct comfort preferences.

Advantages to trying the Fan/On setting:

  • You can keep the temperature in every room more balanced by permitting the fan to keep circulating air.
  • Indoor air quality should improve because continuous airflow will keep moving airborne contaminants through the air filter.
  • A smaller amount of start-stop cycles for the blower fan helps lengthen its life span. As the air handler is typically part of the furnace, this means you might avoid needing furnace repair.

Disadvantages to using the Fan/On setting:

  • A nonstop fan will likely add to your energy bills slightly.
  • Constant airflow could 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

Through the summer, warm air can linger in unfinished spaces like the attic or an attached garage. If you leave the fan on, your HVAC system can pull this warm air into the rest of your home, compelling the HVAC system to work harder to maintain the desired temperature. In extreme heat, this can lead to needing AC repair more quickly as wear and tear increases.

The reverse can occur in the winter. Cooler spaces like a basement will hold onto cooler air, which may 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 keep warm.

If you’re still trying to figure out if you should switch to the fan/on setting, keep in mind that every home and family’s comfort needs are different. Leaving the HVAC system’s fan on may work for you if:

Someone in your household has allergies. Allergies and other respiratory conditions can be tough 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 deal with stubborn hot and cold spots that quickly return to a temperature different from the rest of the house. The fan setting might help minimize these changes by constantly refreshing each room’s supply of air.