Johnstone Supply is one of the leading cooperative wholesale distributors in the United States specializing in heating, ventilating and air Conditioning (HVAC). Located in San Diego, Calif., the company offers a variety of products, such as air conditioning supplies and parts. In addition, Johnstone Supply provides technical advice as well as training seminars printing an annual catalog featuring more than 30,000 HVAC parts, supplies and equipment. The company operates more than 340 independently owned store locations throughout the United States.