The term “diesel fuel fired heaters” has come to represent a complete market of air and coolant heaters which use diesel fuel as their primary power supply. Their purpose is to provide an independent heat source for any system which has diesel fuel and battery power available. The application of this technology varies greatly and has been used for everything from auxiliary heat in the treatment areas of ambulances to the replacement of engine idling as the primary heat source for the engine and cab compartment of over the road trucks during layovers, deliveries and breaks.Diesel fuel fired heater technology was developed in Europe in the 1940's. Since its inception, the technology has become widely accepted and the market for these products has grown significantly throughout Europe. In the 1980's, the technology and its associated products were imported into the North American market. Market differences and performance issues have hampered the products acceptance to date. Manufacturers that have failed to recognize and adjust for the differences in market expectations, fuel composition, operating voltages, and system complexity, have given the industry a black eye. As 1994 approaches with its new EPA requirements and the inherent introduction of new, more efficient, engines which produce less heat, the need for diesel fuel fired heaters will become even greater and the application of them will become more sophisticated.