The add air hood is also known as an auxiliary air, make-up air, induced air, or balanced air. The add air hood was initially seen as a simple and dramatic way to conserve energy and reduce energy costs since the hood provides up to 70% of the hood exhaust requirements. With a bypass similar to the bypass hood, outside air is introduced through the add air plenum, thus minimizing the amount of conditioned room air required. Caution should be used when considering this type of hood due to the balancing of the air coming in from the outside.