When the weather starts to cool off, you might be thinking about how you’ll make the most of your heating and cooling. After all, HVAC bills routinely make up a significant chunk of your monthly electric bill. To try and find ways to reduce costs, some people take a closer look at their thermostat. Is there a setting they could use to improve efficiency?

The majority of thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a typical cycle, what will the fan setting provide for an HVAC system? This guide will help. We’ll walk through just what the fan setting is and how you can use it to save money in the summer or winter.

Should I Use My Thermostat’s Fan Setting?

For the majority of thermostats, the fan setting indicates that the air handler’s blower fan keeps running. A few furnaces will operate at a low level in this setting, but in general heating or cooling isn’t being produced. The ‘Auto’ setting, in contrast, will run the fan over a heating or cooling cycle and turn it off after the cycle is finished.

There are pros and cons to trying the fan setting on your thermostat, and the ideal option {will|can|should]] depend on your unique comfort requirements.

Advantages to switching to the Fan/On setting:

  • You can keep the temperature in every room more consistent by enabling the fan to keep circulating air.
  • Indoor air quality will be highest since steady airflow will keep passing airborne pollutants into the air filter.
  • A smaller amount of start-stop cycles for the system’s fan helps lengthen its life span. Since the air handler is typically part of the furnace, this means you can avoid needing furnace repair.

Downsides to utilizing the Fan/On setting:

  • A continuous fan could increase your energy bills by a small margin.
  • Nonstop airflow could clog your air filter up more quickly, increasing the frequency you should replace it.

Which Setting for My Thermostat? Fan or Auto in Summer/Winter

During the summer, warm air may stick around in unfinished spaces including the attic or an attached garage. If you leave the fan on, your HVAC system might pull this warm air into the rest of your home, forcing the HVAC system to work more to preserve the preferred temperature. In serious heat, this could lead to needing AC repair more often as wear and tear grows.

The reverse can occur over the winter. Cooler spaces such as a basement will hold onto cooler air, which can eventually flow into the rest of your home. Keeping the fan on may pull 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, don’t forget that every home and family’s comfort needs will vary. Leaving the HVAC system’s fan on might be best for you if:

Someone in your household has allergies. Allergies and other respiratory conditions can be stressful on the family. Leaving the fan on can help to improve indoor air quality, helping your family breathe easier.

Your home has hot and cold spots. All kinds of homes wrestle with difficult hot and cold spots that quickly return to a temperature different from the rest of the house. The fan setting should help limit these changes by constantly refreshing each room’s ventilation.