When the weather is cooling off, you may be concerned about how you’ll make the most of your heating and cooling. After all, HVAC expenses can add up to a significant portion of your monthly electric bill. To figure out new ways to reduce costs, some owners take a closer look at their thermostat. Maybe there’s a setting they should use to boost efficiency?

The bulk of thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a regular cycle, what does the fan setting provide for an HVAC system? This guide will help. We’ll share what exactly the fan setting is and how you can use it to reduce costs in the summer or winter.

Should I Use My Thermostat’s Fan Setting?

For the bulk of thermostats, the fan setting indicates that the air handler’s blower fan stays on. Certain furnaces can operate at a low level with this setting, but for the most part heating or cooling isn’t being produced. The ‘Auto’ setting, in contrast, will turn on the fan through a heating or cooling cycle and switch it off when the cycle is complete.

There are benefits and drawbacks 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 enabling the fan to keep running.
  • Indoor air quality will be highest as steady airflow will keep moving airborne contaminants through the air filter.
  • Fewer start-stop cycles for the blower fan helps extend its life span. As the air handler is often connected to the furnace, this means you might avoid needing furnace repair.

Downsides to using the Fan/On setting:

  • A nonstop fan can raise your energy costs 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

In the summer, warm air may stick around in unfinished spaces such as the attic or an attached garage. If you use the fan setting, your HVAC system might draw this warm air into the rest of your home, forcing the HVAC system to work harder to keep up with the preferred temperature. In serious heat, this may lead to needing AC repair more often as wear and tear gets worse.

The opposite can take place over the winter. Cooler spaces such as a basement will hold onto cooler air, which may eventually make its way into the rest of your home. Leaving the fan setting on may draw more cold air upward, increasing the amount of heating you need to remain warm.

If you’re still trying to determine 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 ideal for you if:

Someone in your household suffers from allergies. Allergies and similar respiratory conditions can be hard on the family. Leaving the fan on is more likely to enhance indoor air quality, helping your family breathe easier.

Your home experiences 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 might help limit these changes by constantly refreshing each room’s supply of air.