The Pros and Cons of Setting Your AC Fan to "On"

“Should I set my HVAC fan to on?” is something our customers ask us regularly. The easy answer to that question is: “it depends.” Below are the pros and cons of using the “on” setting, which may help shed light on the answer that’s right for you.

Pros to setting your fan to “on”:

• Keeping the fan on creates a more even distribution of heating and cooling by continuously circulating the air in your home — reducing hot and cold spots in your home.
• Less frequent starts and stops can reduce wear and tear, possibly promoting longer fan life.
• Leaving the fan on 24/7 ensures cleaner air, as the air is pulled through the filters in your system. This can be of great benefit to people with allergies —especially if you have the proper filters.

Cons to setting your fan to “on”:

• Electrical costs could be excessive due to the constant demand for electricity.
• Your filters will need replacing more frequently because you are constantly pulling air through them.
• During the summer months, the ducts in your attic and close to your walls can fill with warm air, resulting in the fan blowing hot air into your house. This may cause you to run your cooling system more often.

Families and individuals with severe allergies or unusually dusty homes could benefit from running the fan constantly. Still, if you only need to keep your house cool and comfortable, it may be better to use the "auto" setting, which triggers the fan only when cooling is required.

If you are not sure which answer is correct for you, contact an experienced HVAC professional.