US Air Conditioning supply houses Inc. 1250 N Marshall Ave. El Cajon CA 92020 is a wholesale supply house of HVAC parts equipment and supplies. They are the largest privately owned HVAC supply house in the world. Areas Served: US Air Conditioning supply houses operates 46 HVAC supply houses in California Nevada Utah Idaho and Arizona. What Brands Does US Air Conditioning Sell? US Air Conditioning supply houses carries name brand HVAC supplies from Aermec Broan Carel Coolerado Eaton First Company Fridrich Johnson Controls Magicaire Mars Modine Mitsubishi Mutiaqua Raypak Source1 Sporlan Unico Venstar as well as many others.