Once the weather starts to cool off, you may be thinking about how you’ll take full advantage of your heating and cooling. After all, HVAC costs routinely contribute a large chunk 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 could use to boost efficiency?

The majority of thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a normal cycle, what can the fan setting offer for an HVAC system? This guide will help. We’ll walk through precisely what the fan setting is and whether you can use it to cut costs in the summer or winter.

How Do I Access the Fan Setting on My Thermostat?

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

There are advantages and disadvantages to using the fan setting on your thermostat, and whether you do or don’t {will|can|should]] depend on your distinct comfort needs.

Advantages to switching to the Fan/On setting:

  • You can keep the temperature in every room more consistent by allowing the fan to keep circulating air.
  • Indoor air quality can increase since constant airflow will keep moving airborne contaminants into the air filter.
  • Fewer start-stop cycles for the HVAC fan helps expand its life span. Since the air handler is usually part of the furnace, this means you could avoid needing furnace repair.

Disadvantages to utilizing the Fan/On setting:

  • A constant fan will likely raise your energy costs slightly.
  • Nonstop airflow may clog your air filter in a shorter amount of time, increasing the frequency you’ll need to 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 may linger in unfinished spaces such as the attic or an attached garage. If you use the fan setting, your HVAC system may draw this warm air into the rest of your home, pushing the HVAC system to work harder to keep up with the desired temperature. In extreme heat, this can lead to needing AC repair more regularly as wear and tear increases.

The opposite can take place over the winter. Cooler spaces like a basement will hold onto cooler air, which will eventually make its way into the rest of your home. Leaving the fan running will sometimes pull more cold air upward, increasing the amount of heating you need to keep warm.

If you’re still trying to figure out if you should switch to the fan/on setting, keep in mind that every home and family’s comfort needs are different. Leaving the HVAC system’s fan on could be best 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 improve indoor air quality, helping your family breathe easier.

Your home deals with hot and cold spots. Lots of homes deal with stubborn 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 steadily refreshing each room’s supply of air.