When the weather begins to cool off, you are probably concerned about how you’ll make the most of your heating and cooling. After all, HVAC costs can add up to a big portion of your monthly electric bill. To learn new ways to reduce costs, some homeowners look closer at their thermostat. Maybe there’s a setting they could use to improve efficiency?

The bulk of thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a normal cycle, what can the fan setting provide for your HVAC system? This guide should help. We’ll walk through precisely 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 indicates that the system’s blower fan keeps running. A few furnaces may continue to run at a low level with this setting, but in most cases heating or cooling isn’t being made. 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 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 utilizing 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 can increase because steady airflow will keep passing airborne pollutants into 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 can avoid needing furnace repair.

Disadvantages to switching to the Fan/On setting:

  • A constant fan could add to your energy expenses somewhat.
  • Continuous airflow may clog your air filter soon, increasing the frequency you will want to replace it.

Which Setting for My Thermostat? Fan or Auto in Each Season

During the summer, warm air can stick around in unfinished spaces such as the attic or an attached garage. If you leave the fan on, your HVAC system might draw this warm air into the rest of your home, compelling the HVAC system to work harder to maintain the desired temperature. In severe heat, this could lead to needing AC repair more regularly as wear and tear grows.

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

If you’re still trying to figure out if you should use the fan/on setting, don’t forget that every home and family’s comfort needs are not the same. 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 tough on the family. Leaving the fan on is more likely to improve indoor air quality, helping your family breathe easier.

Your home deals with hot and cold spots. Many homes deal 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.