FFU, laminar flow hood, or high-efficiency air outlet: which should you choose for terminal air supply in a cleanroom?
FFU, laminar flow hood, or high-efficiency air outlet: which should you choose for terminal air supply in a cleanroom?
April 27, 2026
When designing a cleanroom, the selection of terminal air supply equipment often determines the initial investment and operating costs. Fan filter unit (FFU), laminar flow hoods, and high-efficiency air outlets may seem similar in function, but they differ fundamentally in structure and application.
Fan filter unit (FFU)
KLC fan filter unit (FFU) are modular terminal units with built-in fans and filters. They are characterized by their self-powered operation, independent adjustment, and elimination of the need for large air conditioning units. KLC fan filter unit (FFU) are simple to install, highly expandable, and reduce localized system resistance by eliminating the need for long-distance ductwork. KLC fan filter unit (FFU) are suitable for large-area, high-class (e.g., Class 100, Class 1000) cleanrooms or electronic cleanrooms requiring flexible layout.
Laminar flow hood
KLC laminar flow hoods also come with built-in fans, but their design emphasizes the uniformity and unidirectionality of airflow. They are characterized by extremely high filtration efficiency (typically equipped with H14 or U15 grade filters), and the air distribution plate ensures a vertically downward laminar flow effect. KLC laminar flow hoods can create localized Class 100 clean environments in lower-level environments (such as Class 10,000 areas). KLC laminar flow hoods are suitable for areas with extremely high local cleanliness requirements, such as filling stations, weighing rooms, and the core areas of operating rooms in pharmaceutical workshops.
High-efficiency air outlet
This is a passive air supply terminal that does not have its own fan. The KLC high-efficiency air supply outlet relies on the central air conditioning system's fan to deliver air through ducts. It consists of a plenum chamber, a high-efficiency filter, and a diffuser. Its advantages include low unit price, simple structure, and relatively easy maintenance (only filter replacement is required). The KLC high-efficiency air supply outlet is suitable for non-uniform flow cleanrooms (such as Class 10,000 and Class 100,000) with sufficient central air conditioning pressure and a reasonable duct layout.
While the unit cost of a KLC FFU is higher than that of a high-efficiency air supply outlet, in large-scale projects, KLC FFUs can save on a significant amount of air supply ductwork and complex variable frequency control systems, so the overall cost may not be higher. Cleanliness level: For Class 100 and above (ISO 5), KLC FFUs or laminar flow hoods are recommended as the first choice; for Class 10,000 and below (ISO 7/8), KLC high-efficiency air supply outlets offer better cost-effectiveness. Space constraints: If the ceiling space in the factory is limited and large air ducts cannot be installed, KLC FFUs are the only option.
Choosing the right equipment can not only reduce energy consumption but also improve the stability of the clean environment. KLC offers a full range of terminal air supply systems, from FFUs to various air outlets, to meet the needs of different levels of engineering projects.