When the weather starts to cool off, you may be thinking about how you’ll make the most of your heating and cooling. After all, HVAC expenses frequently contribute a large portion of your monthly electric bill. To try and find ways to save, some homeowners look closely at their thermostat. Could there be a setting they should use to increase efficiency?

The bulk of thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a normal cycle, what will the fan setting provide for the HVAC system? This guide should help. We’ll walk through just what the fan setting is and when you can use it to reduce costs during the summer or winter.

My Thermostat Has a Fan Setting?

For most thermostats, the fan setting indicates that the HVAC blower fan keeps running. Some furnaces will generate heat at a low level with this setting, but in general heating or cooling isn’t being produced. The ‘Auto’ setting, in contrast, will run the fan through a heating or cooling cycle and turn it off when the cycle is over.

There are advantages and disadvantages to trying the fan setting on your thermostat, and what’s ideal {will|can|should]] depend on your distinct comfort preferences.

Advantages to switching to the Fan/On setting:

  • You can keep the temperature throughout your home more consistent by enabling the fan to keep running.
  • Indoor air quality can increase since steady airflow will keep passing airborne pollutants through the air filter.
  • Fewer start-stop cycles for the HVAC fan helps extend its life span. As the air handler is typically connected to the furnace, this means you might avoid needing furnace repair.

Downsides to utilizing the Fan/On setting:

  • A nonstop fan will likely raise your energy expenses somewhat.
  • Continuous airflow may clog your air filter in a shorter amount of time, increasing the frequency you will want to replace it.

Should My Thermostat Be on? Fan or Auto in Summer/Winter

During the summer, warm air will sometimes stick around in unfinished spaces like the attic or an attached garage. If you leave the fan on, your HVAC system might pull this warm air into the rest of your home, compelling the HVAC system to work more to keep up with the desired temperature. In serious heat, this can result in needing AC repair more often 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 may eventually drift into the rest of your home. Leaving the fan running will sometimes pump more cold air upward, increasing the amount of heating you need to remain warm.

If you’re still trying to determine if you should try 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 suffers from allergies. Allergies and similar respiratory conditions can be stressful 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. Many homes wrestle 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 supply of air.