As the weather is cooling off, you are probably wondering about how you’ll take full advantage of your heating and cooling. After all, HVAC costs can contribute a big chunk of your monthly electric bill. To try and find ways to reduce costs, some people look closely at their thermostat. Maybe there’s a setting they should use to increase efficiency?

Most thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a normal cycle, what will 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 reduce costs in the summer or winter.

What Is the Fan Setting on My Thermostat?

For the bulk of thermostats, the fan setting signifies that the system's blower fan stays on. Some furnaces can run at a low level with this setting, but in most cases heating or cooling isn’t being produced. The ‘Auto’ setting, on the other hand, will start the fan during a heating or cooling cycle and switch it off once the cycle is finished.

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

Advantages to using the Fan/On setting:

  • You can keep the temperature throughout your home more consistent by enabling the fan to keep running.
  • Indoor air quality will be highest because constant airflow will keep forcing airborne particles into the air filter.
  • A smaller number of start-stop cycles for the blower fan helps lengthen its life span. Since the air handler is usually a component of the furnace, this means you could prevent the need for furnace repair.

Downsides to switching to the Fan/On setting:

  • A nonstop fan can add to your energy bills slightly.
  • Continuous airflow could clog your air filter up more quickly, increasing the frequency you’ll need to replace it.

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

Through the summer, warm air will sometimes 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 maintain the preferred temperature. In extreme heat, this may result in needing AC repair more regularly as wear and tear increases.

The opposite can occur during 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 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 might be best for you if:

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

Your home deals with hot and cold spots. Lots of homes wrestle with persistent hot and cold spots that quickly return 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.