Once the weather begins to cool off, you might be thinking about how you’ll make the most of your heating and cooling. After all, HVAC costs frequently add up to a large portion of your monthly electric bill. To figure out new ways to reduce costs, some people look closely at their thermostat. Is there a setting they could use to boost efficiency?

Most thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a regular cycle, what will the fan setting offer for your HVAC system? This guide will help. We’ll share just what the fan setting is and whether you can use it to reduce costs over the summer or winter.

What Is the Fan Setting on My Thermostat?

For the majority of thermostats, the fan setting means that the HVAC blower fan stays on. Some furnaces may continue to generate heat at a low level with this setting, but in most cases heating or cooling isn’t being made. The ‘Auto’ setting, in contrast, will run the fan over a heating or cooling cycle and shut it off after the cycle is complete.

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

Advantages to trying the Fan/On setting:

  • You can keep the temperature in every room more consistent by permitting the fan to keep generating airflow.
  • Indoor air quality can increase since continuous airflow will keep moving airborne pollutants into the air filter.
  • Fewer start-stop cycles for the system's fan helps lengthen its life span. Because the air handler is typically a component of the furnace, this means you might minimize the risk of needing furnace repair.

Disadvantages to using the Fan/On setting:

  • A continuous fan will likely raise your energy costs slightly.
  • Constant airflow may clog your air filter soon, increasing the frequency you will want to replace it.

Should My Thermostat Be on Fan or Auto in Summer/Winter

Through the summer, warm air will sometimes persist in unfinished spaces such as the attic or an attached garage. If you keep the fan running, your HVAC system can pull this warm air into the rest of your home, compelling the HVAC system to work harder to maintain the preferred temperature. In serious heat, this could lead to needing AC repair more quickly as wear and tear grows.

The reverse can occur in the winter. Cooler spaces such as a basement will hold onto cooler air, which may eventually flow into the rest of your home. Leaving the fan running could draw 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, don’t forget that every home and family’s comfort needs are different. Leaving the HVAC system’s fan on might be best for you if:

Someone in your household has allergies. Allergies and similar respiratory conditions can be tough on the family. Leaving the fan on is more likely to enhance indoor air quality, helping your family breathe easier.

Your home experiences hot and cold spots. Lots of homes deal 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 consistently refreshing each room’s airflow.