Makeup air in a kitchen is replacement air supplied to offset the volume of air removed by exhaust hoods, maintaining proper building pressure and preventing negative pressure conditions. When a kitchen exhaust hood removes air from a space, makeup air must be introduced to prevent the creation of a vacuum that could draw outdoor air through doors, windows, or other openings. This is a critical component of balanced kitchen ventilation systems in commercial facilities.
Technical Details
Makeup air systems typically supply 70 to 90 percent of the exhaust hood’s CFM capacity, with the remaining air drawn from adjacent spaces in the building. The makeup air can be delivered through ceiling diffusers, wall vents, or dedicated ductwork from rooftop units. In commercial kitchens, makeup air is often heated or cooled to minimize thermal loads on the cooking area, with supply temperatures typically set between 68 and 75 degrees Fahrenheit.
Applications
Makeup air systems are required in all commercial kitchen installations per NFPA 96 standards and are recommended in residential kitchens with powerful exhaust systems. Dedicated makeup air units can improve comfort and reduce HVAC strain.
Practical Significance
Proper makeup air supply prevents backdrafting of combustion appliances, reduces HVAC system strain, improves kitchen comfort, and ensures compliance with mechanical codes and standards for balanced ventilation systems.