Once the weather starts to cool off, you might be wondering about how you’ll prepare your heating and cooling. After all, HVAC costs can contribute a large chunk of your monthly electric bill. To figure out new ways to save, some owners look closely at their thermostat. Maybe there’s a setting they should use to increase efficiency?

The majority of thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a typical cycle, what will the fan setting provide for an HVAC system? This guide can help. We’ll share what exactly the fan setting is and whether you can use it to save money over the summer or winter.

What Is the Fan Setting on My Thermostat?

For the bulk of thermostats, the fan setting signifies that the system’s blower fan keeps running. Some furnaces may continue to operate at a low level in this setting, but in general heating or cooling isn’t being generated. The ‘Auto’ setting, conversely, will turn on the fan over a heating or cooling cycle and switch it off after the cycle is finished.

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

Advantages to using the Fan/On setting:

  • You can keep the temperature in each room more balanced by enabling the fan to keep running.
  • Indoor air quality will be highest as steady airflow will keep moving airborne contaminants into the air filter.
  • Fewer start-stop cycles for the system’s fan helps extend its life span. As the air handler is typically a component of the furnace, this means you might avoid needing furnace repair.

Drawbacks to switching to the Fan/On setting:

  • A constant fan will likely raise your energy expenses slightly.
  • Continuous airflow could clog your air filter in a shorter amount of time, increasing the frequency you should replace it.

Should My Thermostat Be on? Fan or Auto in Each Season

In the summer, warm air will sometimes linger in unfinished spaces like the attic or an attached garage. If you keep the fan running, your HVAC system might draw this warm air into the rest of your home, compelling the HVAC system to run longer to maintain the preferred temperature. In severe heat, this could result in needing AC repair more quickly as wear and tear grows.

The opposite can occur in 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 running could pull more cold air upward, increasing the amount of heating you need to keep warm.

If you’re still trying to determine if you should switch to the fan/on setting, don’t forget that every home and family’s comfort needs will vary. Leaving the HVAC system’s fan on may be ideal for you if:

Someone in your household deals with allergies. Allergies and similar respiratory conditions can be stressful on the family. Leaving the fan on is more likely to improve indoor air quality, helping your family breathe easier.

Your home deals with hot and cold spots. Lots of homes deal with difficult hot and cold spots that quickly evolve to a temperature different from the rest of the house. The fan setting might help minimize these changes by steadily refreshing each room’s airflow.