When the weather starts to cool off, you may be thinking about how you’ll prepare your heating and cooling. After all, HVAC expenses can contribute a big chunk of your monthly electric bill. To figure out new ways to lower their HVAC bill, some homeowners look closer at their thermostat. Could there be a setting they can use to boost efficiency?

The bulk of thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a normal cycle, what does the fan setting offer for your HVAC system? This guide can help. We’ll review what exactly the fan setting is and how you can use it to reduce costs during the summer or winter.

Should I Use My Thermostat's Fan Setting?

For the bulk of thermostats, the fan setting indicates that the air handler’s blower fan stays on. Certain furnaces will operate at a low level with this setting, but in general heating or cooling isn’t being generated. The ‘Auto’ setting, conversely, will start the fan during a heating or cooling cycle and switch it off once the cycle is finished.

There are benefits and drawbacks 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 switching to the Fan/On setting:

  • You can keep the temperature in each room more uniform by allowing the fan to keep circulating air.
  • Indoor air quality should improve since steady airflow will keep passing airborne particles through the air filter.
  • A smaller amount of start-stop cycles for the blower fan helps lengthen its life span. Because the air handler is usually connected to the furnace, this means you can prevent the need for furnace repair.

Downsides to utilizing the Fan/On setting:

  • A continuous fan can increase your energy bills slightly.
  • Nonstop airflow could clog your air filter up more quickly, increasing the frequency you should replace it.

{Choosing Between|Should My Thermostat Be on|Which Setting for My Thermostat? Fan or Auto in Summer/Winter

In the summer, warm air will sometimes persist in unfinished spaces including the attic or an attached garage. If you use the fan setting, your HVAC system may gradually move this warm air into the rest of your home, forcing the HVAC system to work harder to preserve the preferred temperature. In severe heat, this could lead to needing AC repair more quickly as wear and tear gets worse.

The opposite can take place over the winter. Cooler spaces like a basement will hold onto cooler air, which can eventually flow into the rest of your home. Keeping the fan on could 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 try the fan/on setting, keep in mind 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 suffers from allergies. Allergies and other respiratory conditions can be stressful on the family. Leaving the fan on is more likely to improve indoor air quality, helping your family breathe easier.

Your home has hot and cold spots. All kinds of homes wrestle with difficult hot and cold spots that quickly return to a temperature different from the rest of the house. The fan setting should help lessen these changes by consistently refreshing each room’s airflow.