What is the purpose of Make-up air?

Make-up air serves a critical role in maintaining balanced air pressure within a building, particularly in areas where there is a significant exhaust of air, such as commercial kitchens or manufacturing facilities. When air is removed from a space—whether through ventilation systems or exhaust fans—a negative pressure can develop. This negative pressure can lead to issues such as doors that are difficult to open, infiltration of unconditioned air, or even backdrafting of combustion appliances, which could pose safety risks.

Introducing make-up air helps replenish the air that has been exhausted, effectively mitigating the risk of large negative pressure. This influx of fresh air ensures that the building maintains an appropriate pressure balance, enhancing overall comfort and functionality.

While improving indoor air quality and regulating temperature can be benefits of a properly balanced ventilation system, they are secondary to the primary function of make-up air, which is to prevent negative pressure in exhausted areas. Allowing more natural light into a building is unrelated to the concept of make-up air and its intended purpose.