QA-Deluxe whole house fans are quiet, and energy efficient. They are modern, ducted fans that hang from the rafters in the attic. They are connected to the ceiling grille with flexible, insulated duct. This keeps the fan noise away from the ceiling opening. They have insulated dampers that close when the fan turns off. The insulation is much better than other fans. The fan body is heavy spun aluminum and there are rubber bushings on the motor mounts to help prevent vibration.