LAAT Series has a main advantage of saving energy by reducing the amount of heat exhausted by the hood. While energy saving can be substantial, the unconditioned airflow can cause discomfort for those working near the hood, thus the amount of conditioned room air that is consumed is reduced. The auxiliary fume hood is a bypass hood with the addition of direct auxiliary air connection to provide unconditioned or partially conditioned outside makeup air. They are designed to save heating and cooling energy costs, they are also provided with additional ductwork, fans, and air tempering facilities.