As the weather starts to cool off, you might be thinking about how you’ll prepare your heating and cooling. After all, HVAC bills frequently contribute a large portion of your monthly electric bill. To try and find ways to lower their HVAC bill, some people look closely at their thermostat. Maybe there’s a setting they should use to boost efficiency?

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

Should I Use My Thermostat’s Fan Setting?

For most thermostats, the fan setting means that the HVAC blower fan keeps running. A few furnaces can run at a low level with this setting, but in general heating or cooling isn’t being produced. The ‘Auto’ setting, conversely, will start the fan through a heating or cooling cycle and shut it off after the cycle is complete.

There are benefits and drawbacks to using 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 every room more uniform by enabling the fan to keep circulating air.
  • Indoor air quality can increase because steady airflow will keep moving airborne particles through the air filter.
  • Fewer start-stop cycles for the blower fan helps extend its life span. Since the air handler is usually a component of the furnace, this means you can avoid needing furnace repair.

Drawbacks to using the Fan/On setting:

  • A nonstop fan can add to your energy bills by a small margin.
  • Constant airflow may 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 may linger in unfinished spaces including the attic or an attached garage. If you leave the fan on, your HVAC system can pull this warm air into the rest of your home, pushing the HVAC system to work more to keep up with the desired temperature. In severe heat, this may result in needing AC repair more regularly as wear and tear increases.

The opposite can occur during the winter. Cooler spaces such as a basement will hold onto cooler air, which will eventually make its way into the rest of your home. Leaving the fan setting on will sometimes draw more cold air upward, increasing the amount of heating you need to keep warm.

If you’re still trying to figure out if you should try 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 may be ideal for you if:

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

Your home has hot and cold spots. Lots of homes wrestle with stubborn hot and cold spots that quickly return to a temperature different from the rest of the house. The fan setting can help limit these changes by consistently refreshing each room’s ventilation.