What makes a gravity furnace different from forced-air systems?

Hello, thank you for reaching out. Gravity furnaces rely on natural airflow instead of blowers, eliminating the need for electricity. If you install the blower accessory - the blower requires the need of electricity in order to work. If you have additional questions, please feel free to reach out over the phone to our Customer Service line at 1-888-901-5460. Have a great rest of your day.