When the weather starts to cool off, you might be thinking about how you’ll take full advantage of your heating and cooling. After all, HVAC costs routinely add up to a large chunk of your monthly electric bill. To figure out new ways to save, some homeowners take a closer look at their thermostat. Could there be a setting they could use to improve efficiency?

The majority of thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a regular cycle, what does the fan setting provide for your HVAC system? This guide should help. We’ll walk through just what the fan setting is and when you can use it to save money during the summer or winter.

Should I Use My Thermostat’s Fan Setting?

For most thermostats, the fan setting indicates that the air handler’s blower fan stays on. Some furnaces may continue to operate at a low level with this setting, but for the most part heating or cooling isn’t being produced. The ‘Auto’ setting, conversely, will turn on the fan during a heating or cooling cycle and turn it off when the cycle is over.

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 personal comfort needs.

Advantages to using the Fan/On setting:

  • You can keep the temperature in each room more consistent by permitting the fan to keep circulating air.
  • Indoor air quality can increase as continuous airflow will keep passing airborne pollutants into the air filter.
  • A smaller amount 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 can minimize the risk of needing furnace repair.

Downsides to utilizing the Fan/On setting:

  • A constant fan could increase your energy expenses slightly.
  • Continuous airflow could clog your air filter up more quickly, increasing the frequency you should replace it.

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

During the summer, warm air will sometimes linger in unfinished spaces including the attic or an attached garage. If you use the fan setting, your HVAC system may draw this warm air into the rest of your home, compelling the HVAC system to work harder to maintain the desired temperature. In extreme heat, this could result in needing AC repair more quickly as wear and tear grows.

The opposite can take place during 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 may draw more cold air upward, increasing the amount of heating you need to remain 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 could be ideal for you if:

Someone in your household deals with allergies. Allergies and other respiratory conditions can be stressful 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 difficult hot and cold spots that quickly return to a temperature different from the rest of the house. The fan setting might help minimize these changes by consistently refreshing each room’s supply of air.