When the weather starts to cool off, you might be wondering about how you’ll prepare your heating and cooling. After all, HVAC costs frequently add up to a significant portion of your monthly electric bill. To figure out new ways to lower their HVAC bill, some homeowners look closer at their thermostat. Maybe there’s a setting they should use to boost efficiency?

Most thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a normal cycle, what will the fan setting provide for an HVAC system? This guide can help. We’ll review what exactly the fan setting is and when you can use it to cut costs in the summer or winter.

What Is the Fan Setting on My Thermostat?

For the bulk of thermostats, the fan setting signifies that the air handler’s blower fan keeps running. Certain furnaces will operate at a low level in this setting, but in general heating or cooling isn’t being made. The ‘Auto’ setting, on the other hand, will turn on the fan during a heating or cooling cycle and turn it off once the cycle is over.

There are advantages and disadvantages to switching on the fan setting on your thermostat, and the ideal option {will|can|should]] depend on your unique comfort preferences.

Advantages to using the Fan/On setting:

  • You can keep the temperature in every room more consistent by permitting the fan to keep running.
  • Indoor air quality can increase since steady airflow will keep passing airborne contaminants into the air filter.
  • A smaller amount 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 prevent the need for furnace repair.

Disadvantages to using the Fan/On setting:

  • A nonstop fan will likely increase your energy bills slightly.
  • Constant airflow may clog your air filter soon, 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 including the attic or an attached garage. If you use the fan setting, your HVAC system might gradually move this warm air into the rest of your home, compelling the HVAC system to work more to keep up with the set temperature. In serious heat, this could lead to needing AC repair more often as wear and tear gets worse.

The opposite can happen during the winter. Cooler spaces such as a basement will hold onto cooler air, which will eventually make its way into the rest of your home. Leaving the fan running may pull more cold air upward, increasing the amount of heating you need to stay 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 may be best for you if:

Someone in your household deals with 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 deals with hot and cold spots. Many 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 limit these changes by consistently refreshing each room’s supply of air.