When the weather starts to cool off, you are probably concerned about how you’ll make the most of your heating and cooling. After all, HVAC bills routinely make up a significant portion of your monthly electric bill. To figure out new ways to lower their HVAC bill, some owners take a closer look at their thermostat. Could there be a setting they can use to boost efficiency?

The bulk of thermostats include both 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 review what exactly the fan setting is and whether you can use it to reduce costs during the summer or winter.

What Is the Fan Setting on My Thermostat?

For the bulk of thermostats, the fan setting means that the HVAC blower fan keeps running. Some furnaces can run at a low level in this setting, but in most cases heating or cooling isn’t being generated. The ‘Auto’ setting, on the other hand, will turn on the fan during a heating or cooling cycle and switch it off after the cycle is complete.

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

Advantages to utilizing the Fan/On setting:

  • You can keep the temperature in each room more uniform by enabling the fan to keep circulating air.
  • Indoor air quality should improve as constant airflow will keep passing airborne pollutants into the air filter.
  • Fewer start-stop cycles for the HVAC fan helps lengthen its life span. Since the air handler is usually connected to the furnace, this means you can minimize the risk of needing furnace repair.

Disadvantages to using the Fan/On setting:

  • A nonstop fan will likely raise your energy costs somewhat.
  • Constant airflow could clog your air filter up more quickly, increasing the frequency you will want to replace it.

Which Setting for My Thermostat? Fan or Auto in Summer/Winter

During the summer, warm air will sometimes stick around in unfinished spaces such as the attic or an attached garage. If you use the fan setting, your HVAC system might draw this warm air into the rest of your home, forcing the HVAC system to run longer to maintain the preferred temperature. In extreme heat, this could lead to needing AC repair more regularly as wear and tear gets worse.

The reverse can take place during the winter. Cooler spaces like a basement will hold onto cooler air, which will eventually make its way into the rest of your home. Leaving the fan setting on will sometimes pull 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 use the fan/on setting, keep in mind that every home and family’s comfort needs are different. Leaving the HVAC system’s fan on might be ideal for you if:

Someone in your household suffers from allergies. Allergies and other respiratory conditions can be hard on the family. Leaving the fan on can help to increase indoor air quality, helping your family breathe easier.

Your home deals with 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 can help lessen these changes by consistently refreshing each room’s airflow.