When the weather starts to cool off, you may be thinking about how you’ll make the most of your heating and cooling. After all, HVAC bills routinely make up a significant piece of your monthly electric bill. To learn new ways to reduce costs, some owners look closer at their thermostat. Maybe there’s a setting they could use to improve efficiency?

Most thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a normal cycle, what will the fan setting offer for the HVAC system? This guide should help. We’ll review what exactly the fan setting is and whether you can use it to save money in the summer or winter.

How Do I Access the Fan Setting on My Thermostat?

For the bulk of thermostats, the fan setting means that the air handler’s blower fan remains on. Some furnaces may continue to operate at a low level with this setting, but in most cases heating or cooling isn’t being generated. The ‘Auto’ setting, conversely, will run the fan over a heating or cooling cycle and turn it off once the cycle is finished.

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

Advantages to switching to the Fan/On setting:

  • You can keep the temperature throughout your home more balanced by allowing the fan to keep circulating air.
  • Indoor air quality should improve because steady airflow will keep moving airborne contaminants through the air filter.
  • A smaller amount of start-stop cycles for the blower fan helps extend its life span. Since the air handler is often part of the furnace, this means you could avoid needing furnace repair.

Drawbacks to using the Fan/On setting:

  • A nonstop fan could add to your energy costs slightly.
  • Nonstop airflow could clog your air filter in a shorter amount of time, increasing the frequency you will want to 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 will sometimes linger in unfinished spaces like the attic or an attached garage. If you keep the fan running, your HVAC system may draw 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 could result in needing AC repair more quickly as wear and tear increases.

The opposite can happen in the winter. Cooler spaces like 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 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 different. Leaving the HVAC system’s fan on might be ideal for you if:

Someone in your household deals with allergies. Allergies and similar respiratory conditions can be tough on the family. Leaving the fan on can help to increase indoor air quality, helping your family breathe easier.

Your home deals with hot and cold spots. Many homes wrestle with difficult hot and cold spots that quickly evolve to a temperature different from the rest of the house. The fan setting should help limit these changes by consistently refreshing each room’s supply of air.