What is the definition of a Rapid Make Up Air Unit? A Rapid Make Up Air Unit, or RMAU, is a type of heating and cooling system used in industrial and commercial buildings. This equipment works to provide a quick replacement for air that has been exhausted from a building due to exhaust fans, doors, or other ventilation openings. The RMAU operates by quickly replacing this exhausted air with fresh air from outside the building. This is done to maintain a comfortable temperature and air quality indoors. RMAUs typically include a blower, heater, cooling coils and filters, and may also include humidifiers and air cleaners. The RMAU is designed to provide an efficient and cost-effective way to maintain a comfortable indoor environment. The air quality and temperature inside the building can be regulated by controlling the RMAU’s speed, temperature, and air flow rate. This system is very important in buildings with frequent air exchanges, as it can help provide a comfortable environment while