When the weather starts to cool off, you might be concerned about how you’ll make the most of your heating and cooling. After all, HVAC costs routinely add up to a significant portion of your monthly electric bill. To try and find ways to lower their HVAC bill, some owners look closer at their thermostat. Is there 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 can the fan setting offer for your HVAC system? This guide should help. We’ll share precisely what the fan setting is and when you can use it to save money over the summer or winter.

Should I Use My Thermostat’s Fan Setting?

For the majority of thermostats, the fan setting indicates that the HVAC blower fan stays on. A few furnaces may continue to run at a low level with this setting, but in general heating or cooling isn’t being made. The ‘Auto’ setting, in contrast, will run the fan through a heating or cooling cycle and turn it off when the cycle is complete.

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

Advantages to trying the Fan/On setting:

  • You can keep the temperature in every room more consistent by allowing the fan to keep running.
  • Indoor air quality will be highest as constant airflow will keep moving airborne particles through the air filter.
  • Fewer start-stop cycles for the system’s fan helps lengthen its life span. As the air handler is typically connected to the furnace, this means you might avoid needing furnace repair.

Drawbacks to switching to the Fan/On setting:

  • A constant fan can raise your energy bills by a small margin.
  • Nonstop airflow could clog your air filter in a shorter amount of time, increasing the frequency you will want to replace it.

Which Setting for My Thermostat? Fan or Auto in Each Season

Through the summer, warm air may persist in unfinished spaces like 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 more to keep up with the preferred temperature. In serious heat, this could result in needing AC repair more quickly as wear and tear grows.

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

If you’re still trying to figure out if you should switch to the fan/on setting, don’t forget that every home and family’s comfort needs are not the same. Leaving the HVAC system’s fan on may 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 increase indoor air quality, helping your family breathe easier.

Your home has hot and cold spots. All kinds of homes wrestle with difficult hot and cold spots that quickly evolve to a temperature different from the rest of the house. The fan setting might help limit these changes by consistently refreshing each room’s ventilation.