Auxiliary fume hood is used in air-conditioned lab. Standard fume hood draw air from the room. Auxiliary fume hood minimizes the consumption of conditioned air for exhaust. In this hood, auxiliary air is brought from outside and introduced at the face of fume hood which shall be utilized for exhaust. This auxiliary air works as make up air. Also, auxiliary air creates air curtain in front of fume hood face so that the conditioned air is prevented entering the hood. However, complete prevention of entering conditioned room air in to the fume hood is not possible. There are chances of escaping auxiliary air inside the room hence, it is necessary that auxiliary air must be preconditioned and pre-filtered before it is brought to the fume hood. Auxiliary fume hood system should provide safe capture and efficient displacement of the fumes during exhaust functioning. The right auxiliary fume hood system will have proper balance of supplementary air, room air and exhaust air. Please do not pressurize the hood with supplementary air that will create turbulence and may deflect the flow of fumes.