What is a rooftop unit (RTU) in commercial roofing?

A rooftop unit (RTU) refers specifically to a packaged air conditioning system that is installed on the roof of a commercial building. These units are self-contained systems that often include both heating and cooling components and are designed for the purpose of effectively controlling the climate within a building. Their placement on the rooftop allows for optimal space utilization and often provides the benefit of keeping mechanical equipment out of the way of the building's occupants, which can minimize noise and aesthetic impact.

In addition to their primary function of regulating indoor temperature, RTUs commonly have features for ventilation, ensuring that fresh air is circulated within the space. This is particularly essential in commercial environments, where maintaining air quality is a crucial consideration.

The other options represent different types of systems or structures that do not align with what an RTU is. A skylight focuses on providing natural lighting, a rainwater collection system addresses water management rather than climate control, and a roof garden pertains to landscape and recreational use on rooftops rather than mechanical air conditioning functions.