Once the weather begins to cool off, you may be thinking about how you’ll make the most of your heating and cooling. After all, HVAC costs routinely make up a large piece of your monthly electric bill. To try and find ways to lower their HVAC bill, some homeowners take a closer look at their thermostat. Maybe there’s a setting they can use to increase efficiency?

Most thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a regular cycle, what will the fan setting provide for the HVAC system? This guide will help. We’ll review what exactly the fan setting is and whether you can use it to reduce costs in the summer or winter.

How Do I Access the Fan Setting on My Thermostat?

For most thermostats, the fan setting means that the air handler’s blower fan remains on. Certain furnaces may continue to run at a low level in this setting, but for the most part heating or cooling isn’t being made. The ‘Auto’ setting, on the other hand, will start the fan over a heating or cooling cycle and turn it off when the cycle is finished.

There are benefits and drawbacks to using the fan setting on your thermostat, and what’s ideal {will|can|should]] depend on your personal comfort needs.

Advantages to using the Fan/On setting:

  • You can keep the temperature throughout your home more balanced by allowing the fan to keep running.
  • Indoor air quality will be highest since continuous airflow will keep passing airborne contaminants into the air filter.
  • A smaller number of start-stop cycles for the HVAC fan helps extend its life span. As the air handler is usually part of the furnace, this means you might prevent the need for furnace repair.

Downsides to using the Fan/On setting:

  • A constant fan will likely raise your energy bills by a small margin.
  • Continuous airflow can clog your air filter up more quickly, increasing the frequency you will want to replace it.

Should My Thermostat Be on? Fan or Auto in Each Season

During the summer, warm air may stick around 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, forcing the HVAC system to work more to preserve the preferred temperature. In extreme heat, this can result in needing AC repair more regularly as wear and tear increases.

The reverse can happen during the winter. Cooler spaces such as a basement will hold onto cooler air, which may eventually drift into the rest of your home. Leaving the fan running may pull more cold air upward, increasing the amount of heating you need to remain warm.

If you’re still trying to decide if you should switch to the fan/on setting, remember that every home and family’s comfort needs are not the same. 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 can help to improve indoor air quality, helping your family breathe easier.

Your home deals with hot and cold spots. All kinds of homes deal with stubborn hot and cold spots that quickly return to a temperature different from the rest of the house. The fan setting might help limit these changes by consistently refreshing each room’s supply of air.