Abstract: Combustion efficiency in an oil burning furnace is increased by the catalization effect of consuming atmospheric air processed to increase its humidity. Atmospheric air is processed by either forcing air into a water container and bubbling it through water by a drawing, natural draft type of action through the container; or atomizing the air. Three embodiments of my invention are disclosed whereby the processed air is conveyed directly into the combustion zone, into an oil gun of an oil burning furnace or both directly into the combustion zone and the oil gun. A further increase in thermal efficiency is achieved by adding ozone to the processed air. By use of a proper nozzle, processed air is directed at the base of the flame within the furnace in substantially the same shape and direction as the flame when employed in the embodiment injecting said air directly into the combustion zone.