It's simple physics. The more exposed surface area in a combustion chamber, the more heat you will capture. The more time room air circulates around a heated surface, the warmer it becomes. The remarkable Clean Burn Heat Exchanger takes maximum advantage of these principles. Compared to inexpensive Blast Tube furnaces which use a simple cylinder shaped combustion chamber, a Clean Burn Heat Exchanger provides approximately 200% more surface area for capturing combustion heat. You get more heat from less oil. The result is a lower stack temperature, more economical use of your used oil, easier maintenance, and longer service life.