Once 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 expenses can add up to a big portion of your monthly electric bill. To try and find ways to lower their HVAC bill, some people look closely at their thermostat. Is there a setting they can use to improve efficiency?

Most thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a normal cycle, what will the fan setting provide for your HVAC system? This guide will help. We’ll review precisely what the fan setting is and how you can use it to save money during the summer or winter.

Should I Use My Thermostat's Fan Setting?

For the bulk of thermostats, the fan setting indicates that the HVAC blower fan stays on. Certain furnaces can run at a low level with this setting, but in general heating or cooling isn’t being generated. The ‘Auto’ setting, in contrast, will turn on the fan over a heating or cooling cycle and switch it off after 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 requirements.

Advantages to using the Fan/On setting:

  • You can keep the temperature in each room more consistent by allowing the fan to keep generating airflow.
  • Indoor air quality should improve as continuous airflow will keep forcing airborne pollutants through the air filter.
  • A smaller number of start-stop cycles for the HVAC fan helps lengthen its life span. Since the air handler is often part of the furnace, this means you might minimize the risk of needing furnace repair.

Downsides to utilizing the Fan/On setting:

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

{Choosing Between|Should My Thermostat Be on|Which Setting for My Thermostat? Fan or Auto in Summer/Winter

During the summer, warm air will sometimes linger in unfinished spaces like the attic or an attached garage. If you keep the fan running, your HVAC system can gradually move this warm air into the rest of your home, compelling the HVAC system to run longer to preserve the preferred temperature. In severe heat, this can lead to needing AC repair more often as wear and tear grows.

The reverse can happen in the winter. Cooler spaces like a basement will hold onto cooler air, which can eventually make its way into the rest of your home. Leaving the fan running may pump more cold air upward, increasing the amount of heating you need to keep warm.

If you’re still trying to decide if you should try the fan/on setting, remember that every home and family’s comfort needs are not the same. Leaving the HVAC system’s fan on could work for you if:

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

Your home deals with hot and cold spots. Many homes deal with persistent hot and cold spots that quickly evolve to a temperature different from the rest of the house. The fan setting can help limit these changes by constantly refreshing each room’s ventilation.