The European transportation industry has a relatively long and varied experience with the use of engine-independent heaters for diesel engines. Because of strict anti-idling laws, high fuel cost, and union mandates relating to driver comfort, heaters are widely used to pre-heat engines and to maintain heat in cabs and cargo areas without idling. This presentation will cover representative heater designs and installations for heavy duty vehicles in various climates, and statistical data on the resulting fuel economies and reduction of noise, emissions, and engine wear. For example, heaters have been found to substantially reduce winter idling; this not only reduces fuel consumption and pollution, but also decreases engine wear. Aside from the economic advantages of this technology, it enables compliance with legislation common in Europe which curtails idling.