How does a metal roof affect air conditioning efficiency and air distribution?

Metal roofs, especially aluminum, have a direct and positive impact on the efficiency of air conditioning systems and air distribution within a building in several ways. First, due to aluminum's high thermal reflectivity, it reduces heat gain from above, easing the load on air conditioning units and reducing the energy consumption required to cool the space. Second, aluminum roofs can be designed with perforated panels that allow air to flow through them. This design transforms the upper space (the plenum) into a massive "air distribution chamber." When conditioned air is pumped into this space, it is evenly distributed and then slowly and quietly flows through thousands of tiny perforations into the room below. This method, known as displacement ventilation, is more efficient and comfortable than forcing air through a limited number of openings, as it prevents unpleasant drafts and ensures a consistent temperature throughout the space. This efficient distribution helps achieve the desired temperature more quickly and with less energy consumption, enhancing the overall efficiency of the air conditioning system.