As the weather begins to cool off, you may be concerned about how you’ll take full advantage of your heating and cooling. After all, HVAC bills frequently make up a big chunk 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 on during a regular cycle, what can the fan setting provide for the HVAC system? This guide should help. We’ll walk through precisely what the fan setting is and how you can use it to save money over the summer or winter.

What Is the Fan Setting on My Thermostat?

For the bulk of thermostats, the fan setting indicates that the system's blower fan remains on. Some furnaces will generate heat at a low level with this setting, but in most cases heating or cooling isn’t being produced. The ‘Auto’ setting, on the other hand, will run the fan through a heating or cooling cycle and switch it off after the cycle is complete.

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

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 can increase since steady airflow will keep moving airborne particles through the air filter.
  • Fewer start-stop cycles for the HVAC fan helps extend its life span. As the air handler is typically part of the furnace, this means you could prevent the need for furnace repair.

Drawbacks to utilizing the Fan/On setting:

  • A continuous fan could raise your energy bills by a small margin.
  • Constant airflow could clog your air filter soon, 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

Through the summer, warm air may stick around in unfinished spaces like the attic or an attached garage. If you use the fan setting, your HVAC system can draw this warm air into the rest of your home, forcing the HVAC system to run longer to preserve the set temperature. In severe heat, this could lead to needing AC repair more quickly as wear and tear grows.

The reverse can happen in the winter. Cooler spaces such as a basement will hold onto cooler air, which will eventually make its way into the rest of your home. Leaving the fan setting on 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, keep in mind that every home and family’s comfort needs are different. Leaving the HVAC system’s fan on may be ideal for you if:

Someone in your household has allergies. Allergies and similar respiratory conditions can be tough on the family. Leaving the fan on should help to enhance 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 return to a temperature different from the rest of the house. The fan setting can help minimize these changes by constantly refreshing each room’s supply of air.