To maintain a kitchen at a negative pressure when extracting kitchen vapours via an extraction unit the air should be simultaneously supplemented. This can result in high energy costs. Energy savings can be achieved by drawing un-tempered outside air directly into the extraction canopy. This air is then forced through the adjustable air slot creating a venture effect which increases the velocity of the air stream. The utilization of this high velocity air stream greatly increases the exhaust efficiency. The Fecon filters are inserted in the canopy at an angle of 45°. The air passes through the semi-circular channels of the Fecon filters and is forced into two directions separating the heavier grease particles from the air stream by centrifugal force. The grease runs off into the grease collecting gutter and is collected in a removable tray. This compensation of approximately 60% exhaust air is a proven energy saver as only 40% tempered air is wasted. The design provides a comfortable work environment as it allows for heat removal and the untampered air is always contained within the canopy and personnel are not subjected to overhead draught.