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

The majority of thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a typical cycle, what can the fan setting provide for your HVAC system? This guide should help. We’ll walk through just what the fan setting is and whether 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 means that the HVAC blower fan stays on. Some furnaces will 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 run the fan through a heating or cooling cycle and switch it off when the cycle is over.

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 using the Fan/On setting:

  • You can keep the temperature throughout your home more uniform by permitting the fan to keep generating airflow.
  • Indoor air quality should improve since continuous airflow will keep moving airborne pollutants into the air filter.
  • Fewer start-stop cycles for the system's fan helps lengthen its life span. Because the air handler is usually part of the furnace, this means you could avoid needing furnace repair.

Downsides to using the Fan/On setting:

  • A continuous fan can add to your energy costs by a small margin.
  • Continuous airflow can clog your air filter soon, 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 stick around in unfinished spaces including 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 run longer to preserve the set temperature. In serious heat, this may result in needing AC repair more regularly as wear and tear increases.

The reverse can happen in the winter. Cooler spaces like a basement will hold onto cooler air, which may eventually make its way into the rest of your home. Leaving the fan running may draw more cold air upward, increasing the amount of heating you need to remain warm.

If you’re still trying to determine if you should use the fan/on setting, keep in mind that every home and family’s comfort needs will vary. Leaving the HVAC system’s fan on might be ideal for you if:

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

Your home has 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 might help minimize these changes by steadily refreshing each room’s airflow.