As the weather starts to cool off, you may be wondering about how you’ll make the most of your heating and cooling. After all, HVAC costs can make up a significant piece of your monthly electric bill. To learn new ways to save, some people look closely at their thermostat. Maybe there’s a setting they could use to boost efficiency?

The majority of thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a typical cycle, what can the fan setting offer for the HVAC system? This guide will help. We’ll walk through just what the fan setting is and when 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 means that the air handler’s blower fan remains on. A few furnaces may continue to generate heat at a low level with this setting, but in most cases heating or cooling isn’t being generated. The ‘Auto’ setting, in contrast, will run the fan over a heating or cooling cycle and switch it off after the cycle is complete.

There are advantages and disadvantages to trying the fan setting on your thermostat, and whether you do or don’t {will|can|should]] depend on your unique comfort requirements.

Advantages to switching to the Fan/On setting:

  • You can keep the temperature in each room more balanced by allowing the fan to keep running.
  • Indoor air quality will be highest since continuous airflow will keep passing airborne contaminants through the air filter.
  • A smaller number of start-stop cycles for the system’s fan helps lengthen its life span. As the air handler is typically part of the furnace, this means you could minimize the risk of needing furnace repair.

Disadvantages to switching to the Fan/On setting:

  • A constant fan can add to your energy expenses by a small margin.
  • Nonstop airflow can clog your air filter in a shorter amount of time, increasing the frequency you’ll need to replace it.

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

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

The reverse can take place during the winter. Cooler spaces like a basement will hold onto cooler air, which will eventually drift into the rest of your home. Keeping the fan on could pull more cold air upward, increasing the amount of heating you need to stay warm.

If you’re still trying to determine if you should try the fan/on setting, keep in mind that every home and family’s comfort needs are not the same. Leaving the HVAC system’s fan on might be best for you if:

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

Your home deals with hot and cold spots. Many homes deal with stubborn hot and cold spots that quickly shift to a temperature different from the rest of the house. The fan setting might help lessen these changes by consistently refreshing each room’s supply of air.