Once the weather begins to cool off, you might be wondering about how you’ll take full advantage of your heating and cooling. After all, HVAC bills can add up to a large chunk of your monthly electric bill. To try and find ways to save, some homeowners look closely at their thermostat. Is there a setting they should use to boost efficiency?

Most thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a normal cycle, what will the fan setting provide for an HVAC system? This guide should help. We’ll walk through just what the fan setting is and how you can use it to save money in 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 stays on. Certain furnaces may continue to generate heat at a low level in this setting, but in general heating or cooling isn’t being produced. The ‘Auto’ setting, conversely, will turn on the fan through a heating or cooling cycle and shut it off when the cycle is over.

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

Advantages to switching to the Fan/On setting:

  • You can keep the temperature in each room more uniform by allowing the fan to keep generating airflow.
  • Indoor air quality will be highest since constant airflow will keep moving airborne contaminants into the air filter.
  • A smaller amount of start-stop cycles for the blower fan helps lengthen its life span. As the air handler is often part of the furnace, this means you might prevent the need for furnace repair.

Disadvantages to switching to the Fan/On setting:

  • A constant fan will likely add to your energy costs by a small margin.
  • Continuous airflow may clog your air filter up more quickly, increasing the frequency you should replace it.

{Choosing Between|Should My Thermostat Be on|Which Setting for My Thermostat? Fan or Auto in Summer/Winter

During the summer, warm air can linger in unfinished spaces such as the attic or an attached garage. If you use the fan setting, your HVAC system might gradually move this warm air into the rest of your home, forcing the HVAC system to work harder to keep up with the desired temperature. In severe heat, this can lead to needing AC repair more often as wear and tear gets worse.

The opposite can take place in the winter. Cooler spaces such as a basement will hold onto cooler air, which may eventually make its way 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 remain warm.

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

Your home has hot and cold spots. Lots of homes wrestle with stubborn hot and cold spots that quickly shift to a temperature different from the rest of the house. The fan setting should help lessen these changes by consistently refreshing each room’s ventilation.