Once the weather starts to cool off, you may be thinking about how you’ll make the most of your heating and cooling. After all, HVAC expenses frequently contribute a large portion of your monthly electric bill. To try and find ways to lower their HVAC bill, some people take a closer look at their thermostat. Is there a setting they should use to boost efficiency?

The bulk of thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a regular cycle, what does the fan setting provide for your HVAC system? This guide will help. We’ll walk through just what the fan setting is and when you can use it to cut costs during the summer or winter.

What Is the Fan Setting on My Thermostat?

For the bulk of thermostats, the fan setting signifies that the air handler’s 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, in contrast, will start the fan over a heating or cooling cycle and switch it off after the cycle is complete.

There are pros and cons to trying the fan setting on your thermostat, and whether you do or don’t {will|can|should]] depend on your unique comfort preferences.

Advantages to switching to the Fan/On setting:

  • You can keep the temperature in every room more consistent by permitting the fan to keep circulating air.
  • Indoor air quality can increase as continuous airflow will keep passing airborne pollutants through the air filter.
  • Fewer start-stop cycles for the blower fan helps lengthen its life span. Since the air handler is often part of the furnace, this means you could avoid needing furnace repair.

Downsides to switching to the Fan/On setting:

  • A nonstop fan can add to your energy expenses slightly.
  • Constant airflow may clog your air filter soon, 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 can linger in unfinished spaces such as 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, compelling the HVAC system to work more to maintain the set temperature. In extreme heat, this may result in needing AC repair more quickly as wear and tear increases.

The reverse can occur in the winter. Cooler spaces like a basement will hold onto cooler air, which can eventually drift into the rest of your home. Leaving the fan running could draw more cold air upward, increasing the amount of heating you need to stay 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 are not the same. Leaving the HVAC system’s fan on could be ideal for you if:

Someone in your household suffers from 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 deals with hot and cold spots. All kinds of homes deal with persistent hot and cold spots that quickly shift to a temperature different from the rest of the house. The fan setting can help limit these changes by constantly refreshing each room’s supply of air.