Air conditioning instrument is one solution to create the conditions of a place as you wish. Application of air conditioning equipment used in houses, offices, market, transportation and other applications where human comfort is not a primary consideration, such as: computers, laboratories, photography, chemical industry, farming, food storage, etc. Hilton Air Conditioning Laboratory Unit A660 contained in the Laboratory of Machine Engineering Muhammadiyah University of Yogyakarta (UMY) provide settings for air conditioning process that can be demonstrated and investigated. performance of maximal heating humidification of Hilton Air Conditioning Laboratory Unit A660 need to know by doing this research. The thermocouples had calibrated with standard thermometer before the tests performed. There are several variation was performed in the pre-heater and re-heater (0kW, 1kW, 2kW). The testing also involved with boiler various 0kW, 2kW and 3kW. The analysis of research used adiabatic saturation assumption where the parameters used were dry bulb temperature (TDB) and wet bulb temperature (TWB) obtained from the test data acquisition.The results showed that the greater power of heater the greater the temperature of dry bulb (TDB) which also affects the increase in enthalphy. Meanwhile, the greater the power boiler that is used causes increased levels of water vapor in the air as shown by the increase in wet bulb temperature wet (TWB) and absolute humidity of air. Warming maximum of 67.5 ° C occurred on fan voltage 100Volt, 0kW boiler, 2kW pre-heater and 1kW re-heater. Maximum quantity of water vapor contained in the duct of 0.0313kgH2O/kg Dry air reached on B suction with fan variation 100Volt, 5kW boiler, pre-heater 2kW, re-heater 2kW.