As the weather is cooling off, you may be wondering about how you’ll prepare your heating and cooling. After all, HVAC bills frequently contribute a large piece of your monthly electric bill. To try and find ways to save, some people take a closer look at their thermostat. Could there be a setting they can use to boost efficiency?

Most thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a normal cycle, what will the fan setting provide for your HVAC system? This guide should help. We’ll walk through what exactly the fan setting is and whether you can use it to cut costs over the summer or winter.

My Thermostat Has a Fan Setting?

For the bulk of thermostats, the fan setting indicates that the system's blower fan stays on. Some furnaces will operate at a low level in this setting, but for the most part heating or cooling isn’t being made. The ‘Auto’ setting, conversely, will turn on the fan through a heating or cooling cycle and switch it off after the cycle is over.

There are advantages and disadvantages to switching on the fan setting on your thermostat, and what's ideal {will|can|should]] depend on your distinct comfort needs.

Advantages to switching to the Fan/On setting:

  • You can keep the temperature in each room more consistent by enabling the fan to keep running.
  • Indoor air quality should improve because continuous airflow will keep passing airborne contaminants through the air filter.
  • A smaller amount of start-stop cycles for the HVAC fan helps expand its life span. Because the air handler is often connected to the furnace, this means you might avoid needing furnace repair.

Disadvantages to utilizing 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 Summer/Winter

In the summer, warm air will sometimes stick around in unfinished spaces such as 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 lead to needing AC repair more often as wear and tear grows.

The opposite can happen during 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 will sometimes 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, 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 similar respiratory conditions can be hard on the family. Leaving the fan on should help to increase indoor air quality, helping your family breathe easier.

Your home deals with hot and cold spots. Lots of homes wrestle with stubborn hot and cold spots that quickly shift to a temperature different from the rest of the house. The fan setting should help lessen these changes by constantly refreshing each room’s ventilation.