As the weather begins to cool off, you may be wondering about how you’ll take full advantage of your heating and cooling. After all, HVAC bills can contribute a big piece of your monthly electric bill. To figure out new ways to lower their HVAC bill, some owners look closer at their thermostat. Could there be a setting they should use to improve efficiency?

Most thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a regular cycle, what will the fan setting provide for your HVAC system? This guide can help. We’ll share just what the fan setting is and when you can use it to cut costs in the summer or winter.

Should I Use My Thermostat’s Fan Setting?

For most thermostats, the fan setting signifies that the air handler’s blower fan keeps running. A few furnaces may continue to operate at a low level with this setting, but in general heating or cooling isn’t being produced. The ‘Auto’ setting, conversely, will start the fan during a heating or cooling cycle and switch it off once the cycle is over.

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

Advantages to switching to the Fan/On setting:

  • You can keep the temperature in every room more consistent by enabling the fan to keep generating airflow.
  • Indoor air quality can increase since steady airflow will keep passing airborne pollutants into the air filter.
  • A smaller number of start-stop cycles for the HVAC fan helps extend its life span. Because the air handler is often part of the furnace, this means you could avoid needing furnace repair.

Downsides to using the Fan/On setting:

  • A nonstop fan could add to your energy bills by a small margin.
  • Continuous airflow can clog your air filter up more quickly, increasing the frequency you’ll need to 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 may persist in unfinished spaces including 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, forcing the HVAC system to run longer to preserve the desired temperature. In extreme heat, this may result in needing AC repair more regularly as wear and tear increases.

The opposite can occur in the winter. Cooler spaces such as a basement will hold onto cooler air, which can eventually drift into the rest of your home. Leaving the fan setting on may pull 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 use the fan/on setting, don’t forget that every home and family’s comfort needs are different. Leaving the HVAC system’s fan on might be best 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 should help to improve indoor air quality, helping your family breathe easier.

Your home deals with 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 limit these changes by constantly refreshing each room’s ventilation.