When the weather is cooling off, you may be thinking about how you’ll make the most of your heating and cooling. After all, HVAC expenses frequently make up a big piece of your monthly electric bill. To try and find ways to lower their HVAC bill, some homeowners look closer at their thermostat. Could there be a setting they could use to boost efficiency?

Most thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a regular cycle, what can the fan setting provide for an HVAC system? This guide can help. We’ll review what exactly the fan setting is and how 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 indicates that the air handler’s blower fan stays on. Certain furnaces may continue to run at a low level with this setting, but in general heating or cooling isn’t being made. The ‘Auto’ setting, conversely, will turn on the fan over a heating or cooling cycle and turn it off once the cycle is over.

There are advantages and disadvantages to switching on the fan setting on your thermostat, and the ideal option {will|can|should]] depend on your distinct comfort needs.

Advantages to using the Fan/On setting:

  • You can keep the temperature in each room more balanced by permitting the fan to keep running.
  • Indoor air quality can increase because continuous airflow will keep forcing airborne contaminants through the air filter.
  • A smaller amount of start-stop cycles for the blower fan helps lengthen its life span. Because the air handler is usually connected to the furnace, this means you could prevent the need for furnace repair.

Disadvantages to using the Fan/On setting:

  • A constant fan can raise your energy expenses somewhat.
  • Nonstop airflow can clog your air filter soon, 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 can stick around in unfinished spaces such as the attic or an attached garage. If you keep the fan running, your HVAC system may draw this warm air into the rest of your home, pushing the HVAC system to work more to keep up with the preferred temperature. In severe heat, this could lead to needing AC repair more regularly as wear and tear grows.

The opposite can happen over the winter. Cooler spaces like a basement will hold onto cooler air, which may eventually drift into the rest of your home. Leaving the fan running may pull 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 will vary. Leaving the HVAC system’s fan on might be ideal for you if:

Someone in your household has allergies. Allergies and other 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 minimize these changes by consistently refreshing each room’s supply of air.