When the weather is cooling off, you might be wondering about how you’ll take full advantage of your heating and cooling. After all, HVAC expenses can make up a significant chunk of your monthly electric bill. To figure out new ways to save, some people take a closer look at their thermostat. Could there be a setting they can use to increase efficiency?

The majority of thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a normal cycle, what will the fan setting provide for your HVAC system? This guide will help. We’ll review just what the fan setting is and when you can use it to reduce costs during the summer or winter.

Should I Use My Thermostat’s Fan Setting?

For the bulk of thermostats, the fan setting signifies that the HVAC blower fan keeps running. Certain furnaces will run at a low level with this setting, but for the most part heating or cooling isn’t being made. The ‘Auto’ setting, conversely, will start the fan during a heating or cooling cycle and turn it off once the cycle is over.

There are benefits and drawbacks to switching on the fan setting on your thermostat, and what’s ideal {will|can|should]] depend on your personal comfort needs.

Advantages to using the Fan/On setting:

  • You can keep the temperature in each room more consistent by allowing the fan to keep running.
  • Indoor air quality should improve since constant airflow will keep forcing airborne particles through the air filter.
  • A smaller amount of start-stop cycles for the blower fan helps expand its life span. As the air handler is typically part of the furnace, this means you could prevent the need for furnace repair.

Downsides to switching to the Fan/On setting:

  • A continuous fan can increase your energy expenses by a small margin.
  • Constant airflow could clog your air filter in a shorter amount of time, increasing the frequency you will want to replace it.

Should My Thermostat Be on? Fan or Auto in Summer/Winter

Through the summer, warm air can stick around in unfinished spaces including the attic or an attached garage. If you leave the fan on, your HVAC system may gradually move this warm air into the rest of your home, compelling the HVAC system to run longer to preserve the desired temperature. In serious heat, this may result in needing AC repair more often as wear and tear increases.

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

If you’re still trying to figure out if you should use the fan/on setting, don’t forget that every home and family’s comfort needs are different. Leaving the HVAC system’s fan on may work 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 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 minimize these changes by constantly refreshing each room’s supply of air.