Roof-top units are a completely different type of machine than traditional heating and air conditioning units. While most systems in homes are known as split systems, roof-top units are, instead, package systems. The difference between split and package systems is simple. A split system has an outdoor cabinet and indoor cabinet that have different components working together to achieve the right climate for your building. With a roof-top unit, every component is packaged together in one large piece of equipment that can sit comfortably atop a building. Because of their size, most roof-top units are used in the context of large-scale buildings, like commercial locations. But their benefits are hard to deny, no matter where they are used.