Once the weather is cooling off, you might be thinking about how you’ll take full advantage of your heating and cooling. After all, HVAC expenses routinely make up a large portion of your monthly electric bill. To learn new ways to reduce costs, some people look closely at their thermostat. Is there a setting they can use to improve efficiency?

Most thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a typical cycle, what does the fan setting offer for your HVAC system? This guide will help. We’ll walk through precisely what the fan setting is and how you can use it to save money during the summer or winter.

What Is the Fan Setting on My Thermostat?

For most thermostats, the fan setting means that the HVAC blower fan remains on. Certain furnaces will operate at a low level in this setting, but in general heating or cooling isn’t being made. The ‘Auto’ setting, in contrast, will run the fan through a heating or cooling cycle and turn it off after the cycle is complete.

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

Advantages to using 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 because steady airflow will keep moving airborne particles through the air filter.
  • A smaller number of start-stop cycles for the system’s fan helps lengthen its life span. As the air handler is often part of the furnace, this means you could minimize the risk of needing furnace repair.

Downsides to switching to the Fan/On setting:

  • A constant fan can raise your energy costs by a small margin.
  • Nonstop airflow can 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 Each Season

In the summer, warm air will sometimes linger in unfinished spaces including the attic or an attached garage. If you leave the fan on, your HVAC system might pull this warm air into the rest of your home, forcing the HVAC system to work more to maintain the preferred temperature. In extreme heat, this could lead to needing AC repair more regularly as wear and tear grows.

The opposite can happen over the winter. Cooler spaces such as a basement will hold onto cooler air, which can 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 decide if you should switch to the fan/on setting, remember 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 deals with allergies. Allergies and similar respiratory conditions can be hard on the family. Leaving the fan on can help to increase indoor air quality, helping your family breathe easier.

Your home has hot and cold spots. Many homes deal with persistent hot and cold spots that quickly return to a temperature different from the rest of the house. The fan setting might help lessen these changes by constantly refreshing each room’s ventilation.