As the weather starts to cool off, you are probably thinking about how you’ll prepare your heating and cooling. After all, HVAC costs routinely make up a significant piece of your monthly electric bill. To learn new ways to save, some owners look closer at their thermostat. Could there be a setting they should use to increase efficiency?

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

What Is the Fan Setting on My Thermostat?

For the bulk of thermostats, the fan setting signifies that the system's blower fan stays on. Certain 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, in contrast, will start the fan during a heating or cooling cycle and turn it off when the cycle is over.

There are advantages and disadvantages to using the fan setting on your thermostat, and whether you do or don’t {will|can|should]] depend on your unique comfort requirements.

Advantages to utilizing the Fan/On setting:

  • You can keep the temperature in each room more balanced by enabling the fan to keep generating airflow.
  • Indoor air quality will be highest because continuous airflow will keep passing airborne pollutants through the air filter.
  • A smaller amount of start-stop cycles for the system's fan helps lengthen its life span. As the air handler is usually a component of the furnace, this means you might minimize the risk of needing furnace repair.

Drawbacks to utilizing the Fan/On setting:

  • A constant fan could raise your energy costs by a small margin.
  • Nonstop airflow may clog your air filter soon, increasing the frequency you should replace it.

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

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

The opposite can take place during the winter. Cooler spaces like a basement will hold onto cooler air, which can eventually flow into the rest of your home. Leaving the fan running will sometimes pump more cold air upward, increasing the amount of heating you need to remain warm.

If you’re still trying to decide if you should use the fan/on setting, don’t forget that every home and family’s comfort needs are not the same. Leaving the HVAC system’s fan on could be ideal for you if:

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

Your home deals with hot and cold spots. Many homes deal with stubborn hot and cold spots that quickly shift to a temperature different from the rest of the house. The fan setting might help lessen these changes by consistently refreshing each room’s supply of air.