Once the weather begins to cool off, you might be thinking about how you’ll take full advantage of your heating and cooling. After all, HVAC costs routinely add up to a significant chunk of your monthly electric bill. To learn new ways to lower their HVAC bill, some owners take a closer look at their thermostat. Could there be a setting they could use to boost efficiency?

The majority of thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a typical cycle, what does the fan setting provide for the HVAC system? This guide should help. We’ll review what exactly the fan setting is and whether you can use it to reduce costs over the summer or winter.

Should I Use My Thermostat's Fan Setting?

For the bulk of thermostats, the fan setting signifies that the air handler’s blower fan stays on. Certain furnaces may continue to generate heat at a low level in this setting, but for the most part heating or cooling isn’t being generated. The ‘Auto’ setting, conversely, will start the fan during a heating or cooling cycle and shut it off when the cycle is complete.

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 requirements.

Advantages to switching to the Fan/On setting:

  • You can keep the temperature in each room more uniform by permitting the fan to keep circulating air.
  • Indoor air quality can increase since continuous airflow will keep passing airborne contaminants into the air filter.
  • A smaller amount of start-stop cycles for the blower fan helps extend its life span. As the air handler is typically a component of the furnace, this means you might avoid needing furnace repair.

Disadvantages to utilizing the Fan/On setting:

  • A nonstop fan will likely add to your energy costs slightly.
  • Constant airflow could clog your air filter up more quickly, increasing the frequency you’ll need to replace it.

{Choosing Between|Should My Thermostat Be on|Which Setting for My Thermostat? Fan or Auto in Each Season

Through the summer, warm air can linger in unfinished spaces like the attic or an attached garage. If you keep the fan running, your HVAC system might pull this warm air into the rest of your home, pushing the HVAC system to work harder to preserve the set temperature. In serious heat, this can lead to needing AC repair more regularly as wear and tear grows.

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

If you’re still trying to decide if you should switch to the fan/on setting, keep in mind that every home and family’s comfort needs will vary. 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 hard 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. Lots of homes deal with difficult hot and cold spots that quickly evolve to a temperature different from the rest of the house. The fan setting can help limit these changes by steadily refreshing each room’s supply of air.