Once the weather starts to cool off, you might be concerned about how you’ll prepare your heating and cooling. After all, HVAC bills can make up a significant portion of your monthly electric bill. To figure out new ways to save, some people take a closer look at their thermostat. Could there be a setting they could use to increase efficiency?

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

Should I Use My Thermostat’s Fan Setting?

For the bulk of thermostats, the fan setting means that the HVAC blower fan keeps running. Certain furnaces will generate heat at a low level with this setting, but for the most part heating or cooling isn’t being produced. The ‘Auto’ setting, on the other hand, will start the fan through a heating or cooling cycle and switch it off after the cycle is complete.

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

Advantages to trying the Fan/On setting:

  • You can keep the temperature in each room more uniform by permitting the fan to keep generating airflow.
  • Indoor air quality can increase since continuous airflow will keep forcing airborne contaminants into the air filter.
  • A smaller amount of start-stop cycles for the HVAC fan helps lengthen its life span. Since the air handler is often part of the furnace, this means you can prevent the need for furnace repair.

Downsides to using the Fan/On setting:

  • A constant fan will likely add to your energy costs slightly.
  • Nonstop airflow may clog your air filter in a shorter amount of time, increasing the frequency you will want to replace it.

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

Through the summer, warm air will sometimes stick around in unfinished spaces including the attic or an attached garage. If you keep the fan running, your HVAC system may gradually move this warm air into the rest of your home, forcing the HVAC system to work more to preserve the set temperature. In severe heat, this may result in needing AC repair more quickly as wear and tear grows.

The reverse can occur 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 setting on could pump more cold air upward, increasing the amount of heating you need to remain warm.

If you’re still trying to determine if you should use 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 be best for you if:

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

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