Once the weather starts to cool off, you may be thinking about how you’ll prepare your heating and cooling. After all, HVAC bills can make up a significant chunk of your monthly electric bill. To learn new ways to lower their HVAC bill, some homeowners take a closer look at their thermostat. Could there be a setting they could use to increase efficiency?

The bulk of thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a regular cycle, what does the fan setting provide for the HVAC system? This guide should help. We’ll walk through what exactly the fan setting is and whether you can use it to save money over the summer or winter.

How Do I Access the Fan Setting on My Thermostat?

For most thermostats, the fan setting signifies that the HVAC blower fan remains on. Certain furnaces will generate heat at a low level in this setting, but in general 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 after the cycle is over.

There are pros and cons to using the fan setting on your thermostat, and what's ideal {will|can|should]] depend on your distinct comfort preferences.

Advantages to utilizing the Fan/On setting:

  • You can keep the temperature in every room more consistent by allowing the fan to keep running.
  • Indoor air quality can increase as continuous airflow will keep passing airborne pollutants into the air filter.
  • A smaller number of start-stop cycles for the HVAC fan helps extend its life span. Since the air handler is usually part of the furnace, this means you might minimize the risk of needing furnace repair.

Downsides to switching to the Fan/On setting:

  • A continuous fan will likely raise your energy costs somewhat.
  • Constant airflow may clog your air filter up more quickly, 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 stick around in unfinished spaces like the attic or an attached garage. If you leave the fan on, your HVAC system might gradually move this warm air into the rest of your home, forcing the HVAC system to work more to preserve the desired temperature. In extreme heat, this may result in needing AC repair more regularly as wear and tear increases.

The opposite can occur in the winter. Cooler spaces like a basement will hold onto cooler air, which can eventually flow into the rest of your home. Leaving the fan setting on will sometimes pump 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 try the fan/on setting, keep in mind that every home and family’s comfort needs will vary. Leaving the HVAC system’s fan on may be best 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 is more likely to increase indoor air quality, helping your family breathe easier.

Your home experiences hot and cold spots. All kinds of homes deal with stubborn hot and cold spots that quickly shift to a temperature different from the rest of the house. The fan setting can help minimize these changes by consistently refreshing each room’s ventilation.