The air curtains seal the entrances while the doors are open with an invisible barrier of air, preventing cold air entering in the winter and cool air escaping in the summer. The Zen air curtain was selected to architecturally fit in with the design of the interior and, in the case of the foyer, match the colour of the doorway.

Mike O’Connor, deputy director at the National Army Museum, said: “The air curtains blend in perfectly, due to matching the RAL colour of the entrance, and are helping to maintain a very comfortable internal temperature for visitors and staff to the museum. They have been running very well so far with no operational issues.”

The Zen air curtain is offered with front and rear panels that can be made in a variety of materials and colours, and can even incorporate signs and elements such as clocks, lighting or digital displays. This makes the model a very popular choice for architects and designers. At the National Army Museum, the Zen above the main entrance was supplied in a matching RAL colour while the shop had the standard finish.

The units are available in a choice of sizes from 1-2.5m in 0.5m increments and can be mounted horizontally above the doorway or vertically to the side, with the possibility of joining two or more units together to cover wide entrances.

Heating can be via electric or LPHW, as was the case at the National Army Museum, or it can be supplied without heating as an air only model.

Low noise, double inlet centrifugal fans with external rotor motors can provide up to 2,7000m3/h of airflow per metre of air curtain (as tested to AMCA 220-05) making the Zen ideal for doorways up to 4.2m high.

A manual controller is included as standard alongside 7m of telephonic cable with RJ45 (Plug & Play) connectors and a hand-held infra-red remote. The National Army Museum selected an optional advanced ‘Clever’ controller to regulate the air curtains, due to the fact that it includes a temperature sensor which automatically adapts to the entrance conditions.