As the weather is cooling off, you are probably thinking about how you’ll prepare your heating and cooling. After all, HVAC costs can contribute a significant piece of your monthly electric bill. To try and find ways to reduce costs, some homeowners take a closer look at their thermostat. Is there a setting they could use to boost efficiency?

The bulk of thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a normal cycle, what will the fan setting offer for your HVAC system? This guide will help. We’ll share just what the fan setting is and how you can use it to cut costs in the summer or winter.

My Thermostat Has a Fan Setting?

For the bulk of thermostats, the fan setting indicates that the HVAC blower fan remains on. Some furnaces can generate heat at a low level in this setting, but in most cases heating or cooling isn’t being produced. The ‘Auto’ setting, on the other hand, will run the fan during a heating or cooling cycle and turn it off after the cycle is finished.

There are pros and cons to trying the fan setting on your thermostat, and whether you do or don’t {will|can|should]] depend on your distinct comfort preferences.

Advantages to trying the Fan/On setting:

  • You can keep the temperature throughout your home more uniform by allowing the fan to keep generating airflow.
  • Indoor air quality will be highest as continuous airflow will keep moving airborne pollutants through the air filter.
  • Fewer start-stop cycles for the HVAC fan helps extend its life span. As the air handler is often connected to the furnace, this means you might prevent the need for furnace repair.

Downsides to switching to the Fan/On setting:

  • A constant fan could increase your energy expenses somewhat.
  • Continuous airflow could clog your air filter in a shorter amount of time, increasing the frequency you’ll need to replace it.

Which Setting for My Thermostat? Fan or Auto in Summer/Winter

During the summer, warm air may linger in unfinished spaces including the attic or an attached garage. If you use the fan setting, your HVAC system may pull this warm air into the rest of your home, compelling the HVAC system to work harder to keep up with the preferred temperature. In severe heat, this can result in needing AC repair more quickly as wear and tear gets worse.

The opposite can occur during the winter. Cooler spaces like a basement will hold onto cooler air, which can eventually make its way into the rest of your home. Leaving the fan running may draw more cold air upward, increasing the amount of heating you need to remain warm.

If you’re still trying to determine if you should try 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 has allergies. Allergies and other respiratory conditions can be hard 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. Many homes deal with persistent hot and cold spots that quickly return to a temperature different from the rest of the house. The fan setting can help lessen these changes by constantly refreshing each room’s ventilation.