Once the weather is cooling off, you are probably concerned about how you’ll prepare your heating and cooling. After all, HVAC costs routinely contribute a significant chunk of your monthly electric bill. To figure out 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?

The bulk of thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a regular cycle, what will the fan setting provide for the HVAC system? This guide will help. We’ll walk through what exactly the fan setting is and how you can use it to cut costs during 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 keeps running. A few furnaces can operate at a low level with this setting, but in general heating or cooling isn’t being generated. The ‘Auto’ setting, conversely, will run the fan during a heating or cooling cycle and turn it off once the cycle is over.

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

Advantages to trying the Fan/On setting:

  • You can keep the temperature in each room more uniform by allowing the fan to keep generating airflow.
  • Indoor air quality should improve since constant airflow will keep moving airborne pollutants into the air filter.
  • A smaller amount of start-stop cycles for the blower fan helps expand its life span. Since the air handler is often connected to the furnace, this means you could avoid needing furnace repair.

Downsides to utilizing the Fan/On setting:

  • A constant fan can add to your energy bills slightly.
  • Continuous airflow can clog your air filter soon, increasing the frequency you’ll need to replace it.

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

During the summer, warm air will sometimes persist in unfinished spaces like 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, compelling the HVAC system to work more to keep up with the set temperature. In severe heat, this could lead to needing AC repair more regularly as wear and tear gets worse.

The reverse can take place in the winter. Cooler spaces such as a basement will hold onto cooler air, which may eventually drift into the rest of your home. Keeping the fan on will sometimes pump 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 might be ideal for you if:

Someone in your household has allergies. Allergies and other respiratory conditions can be hard on the family. Leaving the fan on should help to improve indoor air quality, helping your family breathe easier.

Your home experiences hot and cold spots. Lots 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 ventilation.