As the weather starts to cool off, you might be concerned about how you’ll make the most of your heating and cooling. After all, HVAC expenses routinely add up to a large portion of your monthly electric bill. To figure out new ways to lower their HVAC bill, some owners take a closer look at their thermostat. Could there be a setting they should use to increase efficiency?

The majority 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 offer for an HVAC system? This guide will help. We’ll walk through what exactly the fan setting is and when you can use it to reduce costs in 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. A few furnaces will operate at a low level with this setting, but in general heating or cooling isn’t being produced. The ‘Auto’ setting, in contrast, will run the fan through a heating or cooling cycle and turn it off when the cycle is over.

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

Advantages to trying the Fan/On setting:

  • You can keep the temperature in each room more balanced by allowing the fan to keep circulating air.
  • Indoor air quality can increase because continuous airflow will keep forcing airborne pollutants into the air filter.
  • Fewer start-stop cycles for the HVAC fan helps expand its life span. As the air handler is typically a component of the furnace, this means you might minimize the risk of needing furnace repair.

Downsides to utilizing the Fan/On setting:

  • A continuous fan can add to your energy bills by a small margin.
  • Constant airflow could clog your air filter up more quickly, 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 can linger in unfinished spaces such as the attic or an attached garage. If you leave the fan on, your HVAC system might gradually move this warm air into the rest of your home, forcing the HVAC system to run longer to preserve the preferred temperature. In severe heat, this may result in needing AC repair more quickly as wear and tear grows.

The opposite can occur over the winter. Cooler spaces like a basement will hold onto cooler air, which may eventually make its way 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 might be best for you if:

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

Your home has hot and cold spots. Many homes deal with difficult hot and cold spots that quickly evolve to a temperature different from the rest of the house. The fan setting should help limit these changes by steadily refreshing each room’s ventilation.