As the weather begins to cool off, you may be thinking about how you’ll prepare your heating and cooling. After all, HVAC bills frequently make up a large portion of your monthly electric bill. To try and find ways to save, some homeowners take a closer look at their thermostat. Is there a setting they can use to boost efficiency?

The majority of thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a regular cycle, what will the fan setting offer for your HVAC system? This guide should help. We’ll review just what the fan setting is and how you can use it to cut costs in the summer or winter.

What Is the Fan Setting on My Thermostat?

For most thermostats, the fan setting means that the HVAC blower fan keeps running. Some furnaces may continue to operate at a low level with this setting, but in most cases heating or cooling isn’t being produced. The ‘Auto’ setting, in contrast, will turn on the fan through a heating or cooling cycle and shut it off once the cycle is over.

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

Advantages to utilizing the Fan/On setting:

  • You can keep the temperature in every room more consistent by permitting the fan to keep circulating air.
  • Indoor air quality will be highest since steady airflow will keep moving airborne pollutants through the air filter.
  • A smaller number of start-stop cycles for the blower fan helps lengthen its life span. Since the air handler is typically a component of the furnace, this means you could prevent the need for furnace repair.

Disadvantages to using the Fan/On setting:

  • A continuous fan could increase your energy costs somewhat.
  • Continuous airflow could 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

In the summer, warm air may linger in unfinished spaces such as the attic or an attached garage. If you leave the fan on, your HVAC system can gradually move this warm air into the rest of your home, forcing the HVAC system to run longer to keep up with the set temperature. In extreme heat, this could result in needing AC repair more often as wear and tear increases.

The reverse 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. Keeping the fan on could pump 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, don’t forget 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 similar respiratory conditions can be tough on the family. Leaving the fan on can help to improve indoor air quality, helping your family breathe easier.

Your home experiences hot and cold spots. All kinds of homes deal with persistent hot and cold spots that quickly evolve 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.