When the weather starts to cool off, you might be concerned about how you’ll take full advantage of your heating and cooling. After all, HVAC expenses can contribute a big chunk of your monthly electric bill. To figure out new ways to save, some people take a closer look at their thermostat. Maybe there’s a setting they should use to improve efficiency?

Most thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a normal cycle, what can the fan setting offer for your HVAC system? This guide will help. We’ll share what exactly the fan setting is and when 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 means that the HVAC blower fan stays on. A few furnaces can run at a low level in this setting, but in most cases heating or cooling isn’t being generated. The ‘Auto’ setting, in contrast, will start the fan through a heating or cooling cycle and turn it off once the cycle is complete.

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

Advantages to using the Fan/On setting:

  • You can keep the temperature throughout your home more consistent by enabling the fan to keep circulating air.
  • Indoor air quality can increase as continuous airflow will keep forcing airborne contaminants into the air filter.
  • A smaller number of start-stop cycles for the system’s fan helps extend its life span. Since the air handler is usually connected to the furnace, this means you can avoid needing furnace repair.

Drawbacks to switching to the Fan/On setting:

  • A constant fan could increase your energy costs by a small margin.
  • Continuous airflow could clog your air filter in a shorter amount of time, increasing the frequency you’ll need to replace it.

Should My Thermostat Be on? Fan or Auto in Each Season

Through the summer, warm air may persist in unfinished spaces like the attic or an attached garage. If you leave the fan on, your HVAC system may pull this warm air into the rest of your home, forcing the HVAC system to run longer to keep up with the set temperature. In severe heat, this can result in needing AC repair more quickly as wear and tear increases.

The opposite can occur over the winter. Cooler spaces like a basement will hold onto cooler air, which can eventually drift into the rest of your home. Keeping the fan on could draw more cold air upward, increasing the amount of heating you need to keep warm.

If you’re still trying to determine if you should switch to the fan/on setting, keep in mind 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 has allergies. Allergies and other respiratory conditions can be tough on the family. Leaving the fan on is more likely to improve indoor air quality, helping your family breathe easier.

Your home has 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 might help lessen these changes by constantly refreshing each room’s ventilation.