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 bills routinely contribute a large portion of your monthly electric bill. To learn new ways to lower their HVAC bill, some people look closer at their thermostat. Maybe there’s a setting they should use to improve efficiency?

The bulk of thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a typical cycle, what will the fan setting offer for an HVAC system? This guide will help. We’ll walk through precisely what the fan setting is and how you can use it to reduce costs over the summer or winter.

How Do I Access the Fan Setting on My Thermostat?

For the bulk of thermostats, the fan setting means that the system’s blower fan remains on. Certain furnaces may continue to generate heat at a low level in this setting, but in most cases heating or cooling isn’t being generated. The ‘Auto’ setting, on the other hand, will run the fan over a heating or cooling cycle and shut it off when the cycle is finished.

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 distinct comfort needs.

Advantages to switching to the Fan/On setting:

  • You can keep the temperature in every room more uniform by permitting the fan to keep circulating air.
  • Indoor air quality can increase since constant airflow will keep moving airborne pollutants through the air filter.
  • A smaller amount of start-stop cycles for the HVAC fan helps extend its life span. Because the air handler is usually connected to the furnace, this means you could prevent the need for furnace repair.

Disadvantages to switching to the Fan/On setting:

  • A nonstop fan can raise your energy expenses somewhat.
  • Constant airflow may clog your air filter in a shorter amount of time, increasing the frequency you’ll need to replace it.

Which Setting for My Thermostat? Fan or Auto in Each Season

During the summer, warm air will sometimes persist in unfinished spaces like the attic or an attached garage. If you keep the fan running, your HVAC system can draw this warm air into the rest of your home, compelling the HVAC system to work harder to keep up with the desired temperature. In extreme heat, this can lead to needing AC repair more regularly as wear and tear increases.

The reverse can occur over the winter. Cooler spaces like a basement will hold onto cooler air, which will eventually make its way into the rest of your home. Leaving the fan setting on may pump more cold air upward, increasing the amount of heating you need to remain warm.

If you’re still trying to decide if you should use 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 could be ideal for you if:

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

Your home deals with hot and cold spots. Many homes deal with difficult hot and cold spots that quickly evolve to a temperature different from the rest of the house. The fan setting should help lessen these changes by steadily refreshing each room’s supply of air.