Composite framework

The Liberty composite air handling units are designed and manufactured in the Netherlands by Rosenberg BV. Rosenberg Holland was founded in 1983 and is a completely independent manufacturer of composite roof fans and air handling units.


Rosenberg was the first to introduce the composite roof fan on the market. After the successful introduction of a composite roof fan, Rosenberg proceeded to develop a complete composite air handling unit. Thanks to a high market demand, the production of composite air handling units has grown steadily for years.


ISO 9001 certified since 1994 and VCA certified since 2007.


Today, Liberty has two offices in the Netherlands. The headquarters in Den Dolder where the assembly of the air handling units takes place and the production facility located in Barneveld where the central warehouse and production lines are located.


Product innovation in areas such as energy saving, efficiency, heat recovery systems and high quality components are a continuous process. Together with the feedback from our customers and a high knowledge level of our employees, we are able to supply ready-made concepts and custom-built solutions for the future.

Unique features

Liberty is leading in development, production and supply of composite air handling units and fans. Thanks to their composite structure and casing, the Liberty air handling units are specifically suitable for swimming pools, schools, industry, offices and hospitals.


Benefits of composite air handling units are high corrosion resistance, hygienic, good sound and thermal insulation, cold bridge free (TBI) and UV-resistant. See branches for more specific features per branche.

Corrosion free

Corrosion on casing construction is absolutely impossible. Standard casing construction suitable for application in corrosive environment; classified C5 according to ISO 12944-2. Wet cleaning with detergent solution permissible. No permanent construction damage in case of excessive water exposure caused by calamities. Corrosion resistant casing results in extended maintenace intervals, less mean time to repair and less down time.


Fully closed vapour tight panels with durable double sealing, prevents penetration of moisture.  When moisture and air stay outside, the clean interior of the Liberty Air Handling Units will remain clean. As a result of this sustainable polyurethane sealing the air leakage class of the air handling units have the highest ranking. (L1).


Completely smooth inner surface can be cleaned easily. Resistant against detergents. Critical environments such as hospitals and medical facilities require the highest standards of hygiene and contamination prevention. The Liberty composite air handling units are the most hygienic, smooth and efficient air handling unit for healthcare facilities. If corrosion and contaminated air are not acceptable, the Liberty composite air handling units are the ideal solution.

Thermal performance

Outstanding thermal performance which lie far beyond the minimum
requirements according to the EN 1886.

Thermal transmittance


Thermal bridging


Mechanical strength


Casing air leakage


Filter bypass leakage