This Air Enthalpy Method (Psychrometoric type) is widely used to measure the performance of room airconditioners, a package airconditioners, car air-conditioners and heat exchangers. The equipment use for this methid is capable of measuring temperature, humidity and flow rate of air absorbed into or discharged from both the indoor and the outdoor units of airconditioner at the same time, calculating cooling and heating performance. There are many variations of this equipment.