As the weather is cooling off, you may be concerned about how you’ll make the most of your heating and cooling. After all, HVAC costs frequently contribute a large chunk of your monthly electric bill. To learn new ways to lower their HVAC bill, some owners look closely at their thermostat. Is there a setting they could use to boost efficiency?

The bulk of thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a normal cycle, what does the fan setting provide for the HVAC system? This guide should help. We’ll review what exactly the fan setting is and when you can use it to save money in the summer or winter.

My Thermostat Has a Fan Setting?

For the majority of thermostats, the fan setting indicates that the air handler’s blower fan remains on. Some furnaces will generate heat at a low level in this setting, but for the most part heating or cooling isn’t being generated. The ‘Auto’ setting, on the other hand, will turn on the fan during a heating or cooling cycle and turn it off when the cycle is complete.

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 preferences.

Advantages to trying the Fan/On setting:

  • You can keep the temperature in every room more uniform by allowing the fan to keep running.
  • Indoor air quality can increase because constant 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 often connected to the furnace, this means you could minimize the risk of needing furnace repair.

Disadvantages to using the Fan/On setting:

  • A constant fan will likely increase your energy costs somewhat.
  • Nonstop airflow can clog your air filter up more quickly, increasing the frequency you will want to replace it.

{Choosing Between|Should My Thermostat Be on|Which Setting for My Thermostat? Fan or Auto in Each Season

During the summer, warm air can persist in unfinished spaces including 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, compelling the HVAC system to work harder to maintain the set temperature. In extreme heat, this may result in needing AC repair more quickly as wear and tear gets worse.

The reverse can happen in the winter. Cooler spaces like a basement will hold onto cooler air, which will eventually flow into the rest of your home. Leaving the fan running could draw 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 will vary. Leaving the HVAC system’s fan on might work for you if:

Someone in your household suffers from allergies. Allergies and other 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 experiences hot and cold spots. Lots of homes deal with stubborn 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 consistently refreshing each room’s supply of air.