Alter Airconditioning co., ltd. was established in 1989 as a sub-contracting company mainly involving in the construction Heating, Ventilation and Air-conditioning systems / Clean Rooms / Environmental Buildings and Factories Utilities systems { more}   Alter Airconditioning co.,ltd. , was established in 1989 as a sub-contracting company mainly involving in the construction Heating, Ventilation and Air-conditioning systems / Clean Rooms / Environmental Buildings and Factories Utilities systems. Later in 1991 a joint-venture company with a Japanese Air Handling manufacturer was established to assemble Air Handling Units in Thailand to serve the local Japanese market only. At the end of 2003, the Thai partners decided to split out to serve the local market more comprehensively with newer technology from European manufacturers.