Once the weather starts to cool off, you might be thinking about how you’ll prepare your heating and cooling. After all, HVAC bills routinely contribute a large chunk of your monthly electric bill. To try and find ways to save, some people look closely at their thermostat. Could there be a setting they could use to boost efficiency?

Most thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a normal cycle, what does the fan setting provide for the HVAC system? This guide will help. We’ll share just what 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 majority of thermostats, the fan setting means that the air handler’s blower fan keeps running. Some furnaces will generate heat at a low level in this setting, but for the most part heating or cooling isn’t being generated. The ‘Auto’ setting, in contrast, will start the fan over a heating or cooling cycle and turn it off once the cycle is over.

There are pros and cons to using the fan setting on your thermostat, and the ideal option {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 enabling the fan to keep running.
  • Indoor air quality should improve because steady airflow will keep passing airborne particles through the air filter.
  • A smaller number of 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 avoid needing furnace repair.

Disadvantages to switching to the Fan/On setting:

  • A continuous fan will likely add to your energy bills by a small margin.
  • Nonstop airflow may clog your air filter up more quickly, 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 Each Season

Through the summer, warm air can persist in unfinished spaces including the attic or an attached garage. If you leave the fan on, your HVAC system can draw this warm air into the rest of your home, pushing the HVAC system to run longer to maintain the preferred temperature. In severe heat, this could result in needing AC repair more often as wear and tear gets worse.

The reverse can take place over the winter. Cooler spaces like a basement will hold onto cooler air, which may eventually drift into the rest of your home. Leaving the fan setting 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 not the same. Leaving the HVAC system’s fan on could work for you if:

Someone in your household deals with allergies. Allergies and similar respiratory conditions can be tough on the family. Leaving the fan on is more likely to enhance 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 return to a temperature different from the rest of the house. The fan setting should help limit these changes by consistently refreshing each room’s supply of air.