Bill Johnson taught heating, air conditioning and refrigeration for more than two decades in various technical colleges and factory schools. A graduate of Southern Technical Institute, a branch of Georgia Tech in Atlanta, he also served as service manager for a major manufacturer for six years. Mr. Johnson owned his own HVAC/R business for 10 years and was a member of the Refrigeration Service Engineers Society and the American Society of Heating Refrigerating Air Conditioning Engineers. His authoring credits include three major textbooks on the market today as well as their ancillary materials. He has also written monthly articles, BTU Buddy, that are available online.