Once the weather starts to cool off, you are probably wondering about how you’ll take full advantage of your heating and cooling. After all, HVAC costs can make up a significant chunk of your monthly electric bill. To learn new ways to lower their HVAC bill, some people take a closer look at their thermostat. Could there be a setting they could use to increase efficiency?

Most thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a normal cycle, what will the fan setting provide for the HVAC system? This guide can help. We’ll walk through what exactly the fan setting is and when you can use it to cut costs 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 remains on. Some 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 start the fan over a heating or cooling cycle and switch it off once the cycle is finished.

There are pros and cons to trying the fan setting on your thermostat, and the ideal option {will|can|should]] depend on your distinct comfort needs.

Advantages to using the Fan/On setting:

  • You can keep the temperature in every room more consistent by enabling the fan to keep circulating air.
  • Indoor air quality should improve because continuous airflow will keep forcing airborne contaminants into the air filter.
  • Fewer start-stop cycles for the blower fan helps expand its life span. Because the air handler is usually part of the furnace, this means you can minimize the risk of needing furnace repair.

Downsides to switching to the Fan/On setting:

  • A continuous fan could raise your energy bills by a small margin.
  • Constant airflow could clog your air filter up more quickly, 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 Each Season

Through the summer, warm air will sometimes persist in unfinished spaces such as the attic or an attached garage. If you use the fan setting, your HVAC system can gradually move this warm air into the rest of your home, pushing the HVAC system to work harder to keep up with the preferred temperature. In severe heat, this could result in needing AC repair more often as wear and tear increases.

The opposite can take place during the winter. Cooler spaces such as a basement will hold onto cooler air, which may eventually make its way into the rest of your home. Keeping the fan on may 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 switch to the fan/on setting, remember that every home and family’s comfort needs are different. Leaving the HVAC system’s fan on may be best 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 experiences hot and cold spots. All kinds of homes deal with difficult hot and cold spots that quickly shift to a temperature different from the rest of the house. The fan setting can help limit these changes by steadily refreshing each room’s airflow.