Abstract: Energy conservation structure is provided for a controlled environment room having an opening in a wall thereof through which work is passed and through which room air under pressure may be discharged from the room, thereby to prevent contamination of the room air by contaminants in outside air entering the room through such opening, the energy conservation structure including structure providing suction adjacent to the wall opening to induce the flow of room discharge air thereto, the latter structure being constructed and arranged for communication with structure and apparatus for recycling the discharge air of such induced flow to the controlled environment room.