Designed for the development and performance evaluation of air conditioners and heat pumps. Air conditioners may be in the form of through the wall units, floor standing evaporator split systems and Package Units. The rooms will be side by side simulating “Indoor” and “Outdoor” conditions with temperature, humidity and air flow independently controlled. Each chamber can include an Air Enthalpy Measuring device to enable precise measurement of capacity and efficiency of air conditioners and heat pumps in accordance with the air enthalpy method.