As the weather begins to cool off, you might be thinking about how you’ll prepare your heating and cooling. After all, HVAC costs can add up to a significant portion of your monthly electric bill. To figure out new ways to lower their HVAC bill, some homeowners take a closer look at their thermostat. Maybe there’s a setting they should use to improve efficiency?

The bulk of thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a regular cycle, what can the fan setting provide for the HVAC system? This guide will help. We’ll walk through precisely what the fan setting is and when you can use it to reduce costs in the summer or winter.

How Do I Access the Fan Setting on My Thermostat?

For the majority of thermostats, the fan setting signifies that the system’s blower fan stays on. Some furnaces may continue to run at a low level with this setting, but for the most part heating or cooling isn’t being made. The ‘Auto’ setting, in contrast, will turn on the fan during a heating or cooling cycle and shut it off after 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 unique comfort needs.

Advantages to using the Fan/On setting:

  • You can keep the temperature in every room more balanced by enabling the fan to keep generating airflow.
  • Indoor air quality can increase as constant airflow will keep moving airborne pollutants through the air filter.
  • Fewer start-stop cycles for the system’s fan helps lengthen its life span. Because the air handler is often part of the furnace, this means you might prevent the need for furnace repair.

Downsides to using the Fan/On setting:

  • A constant fan will likely add to your energy bills by a small margin.
  • Continuous airflow can clog your air filter soon, 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

In the summer, warm air will sometimes stick around in unfinished spaces including the attic or an attached garage. If you leave the fan on, your HVAC system can draw this warm air into the rest of your home, forcing the HVAC system to run longer to keep up with the set temperature. In extreme heat, this may result in needing AC repair more quickly as wear and tear grows.

The opposite can occur over the winter. Cooler spaces such as a basement will hold onto cooler air, which may eventually drift into the rest of your home. Leaving the fan setting on will sometimes pull more cold air upward, increasing the amount of heating you need to stay warm.

If you’re still trying to figure out if you should switch to 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 work for you if:

Someone in your household deals with allergies. Allergies and similar respiratory conditions can be hard 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. All kinds of homes wrestle with stubborn hot and cold spots that quickly return to a temperature different from the rest of the house. The fan setting might help lessen these changes by constantly refreshing each room’s supply of air.