When the weather starts to cool off, you are probably concerned about how you’ll take full advantage of your heating and cooling. After all, HVAC costs routinely add up to a big piece of your monthly electric bill. To try and find ways to lower their HVAC bill, some people take a closer look at their thermostat. Could there be a setting they can use to increase efficiency?

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

What Is the Fan Setting on My Thermostat?

For the bulk of thermostats, the fan setting indicates that the HVAC blower fan keeps running. Certain furnaces may continue to operate at a low level in this setting, but in most cases heating or cooling isn’t being generated. The ‘Auto’ setting, on the other hand, will turn on the fan over 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 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 throughout your home more consistent by enabling the fan to keep generating airflow.
  • Indoor air quality should improve because constant airflow will keep moving airborne pollutants into the air filter.
  • Fewer start-stop cycles for the HVAC fan helps extend its life span. Because the air handler is often connected to the furnace, this means you might avoid needing furnace repair.

Disadvantages to using the Fan/On setting:

  • A nonstop fan could add to your energy bills by a small margin.
  • Constant airflow could clog your air filter soon, increasing the frequency you should replace it.

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

Through the summer, warm air will sometimes linger in unfinished spaces including the attic or an attached garage. If you use the fan setting, your HVAC system can pull this warm air into the rest of your home, pushing the HVAC system to run longer to preserve the preferred temperature. In serious heat, this may lead to needing AC repair more regularly as wear and tear increases.

The opposite can take place during the winter. Cooler spaces such as a basement will hold onto cooler air, which may 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 remain warm.

If you’re still trying to figure out if you should try 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 may 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 improve indoor air quality, helping your family breathe easier.

Your home experiences hot and cold spots. Lots of homes deal with persistent 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 airflow.