Over the last few decades, rooftop units have moved ahead with numerous technological advances. Both light (3- to 25-ton units) and large commercial packaged rooftop systems (25 tons and up) have matured in style and substance, now offering cleaner air, added comfort, lower operating costs, more efficient performance, remote controls, and more — making a visit to the supermarket, warehouse, hospital, or other large indoor space much more enjoyable.