Once the weather starts to cool off, you might be concerned about how you’ll prepare your heating and cooling. After all, HVAC costs routinely contribute a big chunk of your monthly electric bill. To figure out new ways to reduce costs, some owners look closely at their thermostat. Maybe there’s a setting they can use to improve efficiency?

The majority of thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a normal cycle, what does the fan setting provide for your HVAC system? This guide will help. We’ll walk through what exactly the fan setting is and whether 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 means that the air handler’s blower fan stays on. Certain furnaces may continue to operate at a low level with this setting, but in general heating or cooling isn’t being produced. The ‘Auto’ setting, conversely, will start the fan through a heating or cooling cycle and shut it off once the cycle is over.

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

Advantages to switching to the Fan/On setting:

  • You can keep the temperature throughout your home more balanced by allowing the fan to keep circulating air.
  • Indoor air quality can increase as continuous airflow will keep forcing airborne contaminants through the air filter.
  • A smaller number of start-stop cycles for the blower fan helps expand its life span. Since the air handler is usually part of the furnace, this means you can avoid needing furnace repair.

Drawbacks to switching to the Fan/On setting:

  • A constant fan will likely increase your energy bills somewhat.
  • Nonstop airflow could clog your air filter up more quickly, 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

Through the summer, warm air will sometimes linger in unfinished spaces such as the attic or an attached garage. If you keep the fan running, your HVAC system can pull this warm air into the rest of your home, forcing the HVAC system to run longer to preserve the desired temperature. In serious heat, this could lead to needing AC repair more quickly as wear and tear gets worse.

The opposite can occur during 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 setting on may 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 ideal for you if:

Someone in your household deals with allergies. Allergies and similar respiratory conditions can be tough on the family. Leaving the fan on is more likely to improve indoor air quality, helping your family breathe easier.

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