As the weather is cooling off, you are probably thinking about how you’ll take full advantage of your heating and cooling. After all, HVAC costs routinely make up a big piece of your monthly electric bill. To try and find ways to reduce costs, some homeowners look closely at their thermostat. Could there be 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 running during a regular cycle, what does the fan setting offer for an HVAC system? This guide can help. We’ll review just what the fan setting is and when you can use it to save money during the summer or winter.

What Is the Fan Setting on My Thermostat?

For the majority of thermostats, the fan setting signifies that the system's blower fan keeps running. Some furnaces will operate at a low level with this setting, but in general heating or cooling isn’t being produced. The ‘Auto’ setting, in contrast, will start the fan during a heating or cooling cycle and turn it off once the cycle is over.

There are advantages and disadvantages to using the fan setting on your thermostat, and the ideal option {will|can|should]] depend on your unique comfort requirements.

Advantages to switching to the Fan/On setting:

  • You can keep the temperature in every room more balanced by allowing the fan to keep circulating air.
  • Indoor air quality will be highest since constant airflow will keep forcing airborne contaminants through the air filter.
  • A smaller amount of start-stop cycles for the HVAC fan helps expand its life span. Because the air handler is usually a component of the furnace, this means you could prevent the need for furnace repair.

Downsides to utilizing the Fan/On setting:

  • A nonstop fan can increase your energy bills somewhat.
  • Constant airflow can clog your air filter soon, increasing the frequency you will want to replace it.

Should My Thermostat Be on Fan or Auto in Summer/Winter

Through the summer, warm air will sometimes persist in unfinished spaces such as the attic or an attached garage. If you leave the fan on, your HVAC system might gradually move this warm air into the rest of your home, pushing the HVAC system to work more to keep up with the set temperature. In severe heat, this may result in needing AC repair more often as wear and tear increases.

The reverse can occur over the winter. Cooler spaces such as a basement will hold onto cooler air, which will eventually flow into the rest of your home. Leaving the fan setting on may draw 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 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 may be best for you if:

Someone in your household has allergies. Allergies and similar respiratory conditions can be hard on the family. Leaving the fan on can help to improve indoor air quality, helping your family breathe easier.

Your home has hot and cold spots. Many homes wrestle with stubborn 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 constantly refreshing each room’s ventilation.