When the weather is cooling off, you might be wondering about how you’ll make the most of your heating and cooling. After all, HVAC bills can make up a large piece of your monthly electric bill. To figure out new ways to save, some people look closer at their thermostat. Could there be a setting they could use to improve efficiency?

Most thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a regular cycle, what does the fan setting offer for an HVAC system? This guide should help. We’ll walk through precisely what the fan setting is and how you can use it to reduce 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 remains on. Certain furnaces will generate heat at a low level with this setting, but in most cases heating or cooling isn’t being produced. The ‘Auto’ setting, on the other hand, will start the fan during a heating or cooling cycle and switch it off after the cycle is over.

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

Advantages to utilizing the Fan/On setting:

  • You can keep the temperature in each room more consistent by enabling the fan to keep running.
  • Indoor air quality will be highest as constant airflow will keep passing airborne pollutants through the air filter.
  • A smaller amount of start-stop cycles for the blower fan helps extend its life span. As the air handler is often connected to the furnace, this means you could minimize the risk of needing furnace repair.

Downsides to using the Fan/On setting:

  • A continuous fan will likely add to your energy expenses somewhat.
  • Continuous airflow can 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 Summer/Winter

During the summer, warm air can linger in unfinished spaces such as the attic or an attached garage. If you keep the fan running, your HVAC system can pull this warm air into the rest of your home, compelling the HVAC system to work more to maintain the desired temperature. In severe heat, this can result in needing AC repair more quickly as wear and tear grows.

The reverse can happen in the winter. Cooler spaces such as a basement will hold onto cooler air, which can eventually flow into the rest of your home. Keeping the fan on could draw more cold air upward, increasing the amount of heating you need to keep warm.

If you’re still trying to determine if you should use the fan/on setting, keep in mind that every home and family’s comfort needs will vary. Leaving the HVAC system’s fan on may work for you if:

Someone in your household deals with allergies. Allergies and other 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 experiences hot and cold spots. All kinds of homes wrestle with difficult hot and cold spots that quickly evolve to a temperature different from the rest of the house. The fan setting can help lessen these changes by consistently refreshing each room’s supply of air.