As the weather begins to cool off, you might be thinking about how you’ll take full advantage of your heating and cooling. After all, HVAC expenses routinely add up to a significant chunk of your monthly electric bill. To figure out new ways to save, some owners look closely at their thermostat. Could there be a setting they could use to boost efficiency?

Most thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a typical cycle, what does the fan setting provide for the HVAC system? This guide can help. We’ll share just what the fan setting is and whether you can use it to cut costs in the summer or winter.

Should I Use My Thermostat’s Fan Setting?

For most thermostats, the fan setting signifies that the system’s blower fan keeps running. Some furnaces can operate at a low level with this setting, but in general heating or cooling isn’t being produced. The ‘Auto’ setting, conversely, will run the fan over a heating or cooling cycle and shut it off once the cycle is finished.

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

Advantages to switching to the Fan/On setting:

  • You can keep the temperature in each room more uniform by allowing the fan to keep circulating air.
  • Indoor air quality should improve as continuous airflow will keep moving airborne contaminants into the air filter.
  • A smaller number of start-stop cycles for the blower fan helps expand its life span. Because the air handler is often connected to the furnace, this means you could avoid needing furnace repair.

Drawbacks to using the Fan/On setting:

  • A continuous fan can increase your energy expenses by a small margin.
  • Nonstop airflow may clog your air filter up more quickly, increasing the frequency you’ll need to replace it.

{Choosing Between|Should My Thermostat Be on|Which Setting for My Thermostat? Fan or Auto in Each Season

In the summer, warm air may stick around in unfinished spaces like the attic or an attached garage. If you leave the fan on, your HVAC system might pull this warm air into the rest of your home, compelling the HVAC system to work harder to keep up with the set temperature. In extreme heat, this could result in needing AC repair more regularly as wear and tear gets worse.

The opposite can happen during the winter. Cooler spaces like a basement will hold onto cooler air, which can eventually drift into the rest of your home. Leaving the fan running will sometimes pull more cold air upward, increasing the amount of heating you need to stay warm.

If you’re still trying to decide if you should use the fan/on setting, remember that every home and family’s comfort needs will vary. Leaving the HVAC system’s fan on might be best for you if:

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

Your home experiences hot and cold spots. Lots of homes wrestle with persistent hot and cold spots that quickly evolve to a temperature different from the rest of the house. The fan setting should help minimize these changes by steadily refreshing each room’s supply of air.