The definition of an AC unit for roof is a system designed to cool the air in a building or home. It is typically installed on the roof and consists of an outdoor unit, an indoor unit, and ductwork. The outdoor unit contains the compressor, condenser, and evaporator coils, while the indoor unit contains the air handler, fan, and filter. The ductwork is used to distribute the cooled air throughout the building or home. The AC unit for roof works by drawing in hot air from the outside, cooling it, and then pushing it back into the building or home. This helps to keep the interior temperature comfortable and reduce energy costs. Additionally, an AC unit for roof can help to reduce humidity levels, improve air quality, and reduce allergens in the air.