When the weather begins to cool off, you might be wondering about how you’ll prepare your heating and cooling. After all, HVAC expenses can contribute a significant portion of your monthly electric bill. To try and find ways to save, some people look closer at their thermostat. Maybe there’s a setting they can use to increase efficiency?

Most thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a regular cycle, what does the fan setting offer for an HVAC system? This guide can help. We’ll review just what the fan setting is and when you can use it to save money during the summer or winter.

Should I Use My Thermostat's Fan Setting?

For the bulk of thermostats, the fan setting signifies that the system's blower fan stays on. A few furnaces may continue to operate at a low level with this setting, but in most cases heating or cooling isn’t being made. The ‘Auto’ setting, on the other hand, will start the fan through a heating or cooling cycle and switch it off once the cycle is complete.

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 personal comfort requirements.

Advantages to using the Fan/On setting:

  • You can keep the temperature in each room more balanced by enabling the fan to keep running.
  • Indoor air quality can increase since steady airflow will keep moving airborne pollutants through the air filter.
  • Fewer start-stop cycles for the HVAC fan helps expand its life span. Because the air handler is often a component of the furnace, this means you can prevent the need for furnace repair.

Downsides to utilizing the Fan/On setting:

  • A constant fan will likely increase your energy costs somewhat.
  • Constant airflow may clog your air filter in a shorter amount of time, 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

In the summer, warm air can stick around 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 keep up with the preferred temperature. In severe heat, this can lead to needing AC repair more regularly as wear and tear gets worse.

The reverse can occur 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 could draw more cold air upward, increasing the amount of heating you need to keep warm.

If you’re still trying to decide 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 could be ideal 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 increase indoor air quality, helping your family breathe easier.

Your home experiences hot and cold spots. Many homes deal with difficult hot and cold spots that quickly return to a temperature different from the rest of the house. The fan setting might help limit these changes by constantly refreshing each room’s airflow.