As the weather begins to cool off, you may be concerned about how you’ll make the most of your heating and cooling. After all, HVAC costs frequently contribute a significant piece of your monthly electric bill. To figure out new ways to reduce costs, some homeowners look closer at their thermostat. Could there be a setting they could use to increase efficiency?

Most thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a normal cycle, what does the fan setting provide for the HVAC system? This guide should help. We’ll share precisely what the fan setting is and whether you can use it to reduce costs over the summer or winter.

What Is the Fan Setting on My Thermostat?

For most thermostats, the fan setting signifies that the system's blower fan keeps running. Some furnaces may continue to run at a low level in this setting, but in most cases heating or cooling isn’t being produced. The ‘Auto’ setting, conversely, will run the fan through a heating or cooling cycle and shut it off when the cycle is over.

There are benefits and drawbacks to using the fan setting on your thermostat, and the ideal option {will|can|should]] depend on your distinct comfort preferences.

Advantages to trying 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 will be highest because continuous airflow will keep passing airborne particles through the air filter.
  • A smaller number of start-stop cycles for the system's fan helps extend its life span. Since the air handler is often part of the furnace, this means you might prevent the need for furnace repair.

Disadvantages to using the Fan/On setting:

  • A nonstop fan could add to your energy expenses slightly.
  • Continuous airflow may clog your air filter up more quickly, 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 may stick around in unfinished spaces including the attic or an attached garage. If you use the fan setting, your HVAC system might pull this warm air into the rest of your home, forcing the HVAC system to work more to preserve the set temperature. In extreme heat, this could lead to needing AC repair more quickly as wear and tear grows.

The reverse can take place over the winter. Cooler spaces such as a basement will hold onto cooler air, which may eventually drift into the rest of your home. Leaving the fan setting on could draw more cold air upward, increasing the amount of heating you need to remain warm.

If you’re still trying to decide if you should use the fan/on setting, remember that every home and family’s comfort needs will vary. Leaving the HVAC system’s fan on might 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 is more likely to enhance indoor air quality, helping your family breathe easier.

Your home experiences hot and cold spots. Lots of homes deal with difficult hot and cold spots that quickly return to a temperature different from the rest of the house. The fan setting should help minimize these changes by consistently refreshing each room’s supply of air.