As the weather begins to cool off, you may be thinking about how you’ll take full advantage of your heating and cooling. After all, HVAC bills routinely contribute a significant portion of your monthly electric bill. To try and find ways to lower their HVAC bill, some homeowners look closely at their thermostat. Could there be a setting they could use to improve efficiency?

Most thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a normal cycle, what will the fan setting offer for an HVAC system? This guide should help. We’ll share 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 the bulk of thermostats, the fan setting signifies that the HVAC blower fan remains on. A few furnaces will generate heat at a low level with this setting, but in most cases heating or cooling isn’t being generated. The ‘Auto’ setting, conversely, will run the fan during a heating or cooling cycle and shut it off once the cycle is over.

There are pros and cons to trying the fan setting on your thermostat, and whether you do or don’t {will|can|should]] depend on your unique comfort preferences.

Advantages to trying the Fan/On setting:

  • You can keep the temperature in every room more uniform by allowing the fan to keep circulating air.
  • Indoor air quality can increase because steady airflow will keep forcing airborne contaminants into the air filter.
  • Fewer start-stop cycles for the HVAC fan helps expand its life span. Because the air handler is often a component of the furnace, this means you might minimize the risk of needing furnace repair.

Disadvantages to switching to the Fan/On setting:

  • A continuous fan can increase your energy costs slightly.
  • Nonstop airflow can 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

During 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 might draw this warm air into the rest of your home, forcing the HVAC system to run longer to preserve the desired temperature. In extreme heat, this can result in needing AC repair more regularly as wear and tear increases.

The reverse can take place during the winter. Cooler spaces such as a basement will hold onto cooler air, which may eventually make its way into the rest of your home. Keeping the fan on could pump more cold air upward, increasing the amount of heating you need to remain warm.

If you’re still trying to figure out if you should try the fan/on setting, keep in mind that every home and family’s comfort needs will vary. Leaving the HVAC system’s fan on might be ideal for you if:

Someone in your household suffers from allergies. Allergies and similar respiratory conditions can be stressful on the family. Leaving the fan on is more likely to increase indoor air quality, helping your family breathe easier.

Your home experiences hot and cold spots. Many homes wrestle with stubborn hot and cold spots that quickly evolve to a temperature different from the rest of the house. The fan setting might help minimize these changes by steadily refreshing each room’s airflow.