In commercial kitchens, exhaust hoods are used to remove the smoke, heat, and odours generated from cooking. To maintain a suitable pressure in the kitchen space, makeup air is typically brought in from the outside to replace the air removed by the exhaust hood. Most kitchen exhaust and makeup fans are interlocked and run at a fixed speed regardless of the level of cooking activity, often 24 hours a day. As such, a large amount of energy is required to condition (heat or cool) this outdoor makeup air flow.
