When the weather is cooling off, you are probably wondering about how you’ll take full advantage of your heating and cooling. After all, HVAC expenses can add up to a significant chunk of your monthly electric bill. To try and find ways to reduce costs, some owners take a closer look at their thermostat. Could there be a setting they could use to increase efficiency?

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

What Is the Fan Setting on My Thermostat?

For the majority of thermostats, the fan setting indicates that the system's blower fan stays on. A few furnaces can operate at a low level in this setting, but in general heating or cooling isn’t being generated. The ‘Auto’ setting, in contrast, will run the fan during a heating or cooling cycle and shut it off when the cycle is over.

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

Advantages to trying the Fan/On setting:

  • You can keep the temperature in each room more consistent by enabling the fan to keep running.
  • Indoor air quality can increase since steady airflow will keep forcing airborne particles through the air filter.
  • A smaller number of start-stop cycles for the HVAC fan helps expand its life span. Because the air handler is often a component of the furnace, this means you might avoid needing furnace repair.

Drawbacks to using the Fan/On setting:

  • A constant fan will likely increase your energy costs by a small margin.
  • Constant airflow may clog your air filter up more quickly, increasing the frequency you should replace it.

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

In the summer, warm air can linger in unfinished spaces including the attic or an attached garage. If you keep the fan running, your HVAC system may draw this warm air into the rest of your home, compelling the HVAC system to work harder to keep up with the desired temperature. In serious heat, this could result in needing AC repair more regularly as wear and tear grows.

The reverse can happen during 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 may pull 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, don’t forget that every home and family’s comfort needs are different. Leaving the HVAC system’s fan on could work for you if:

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

Your home deals with hot and cold spots. All kinds 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 minimize these changes by consistently refreshing each room’s airflow.