VELUX TWR sun tunnel

The VELUX TWR sun tunnel brings natural light into any room where roof or vertical windows cannot be installed. Light reaches the room through a specially designed tunnel leading from the roof of the building to the ceiling. The TWR sun tunnel can also be used where the distance between the ceiling and the roof surface is as much as 6 m.

Sun tunnels consist of three main elements. The first, located on the roof, is a polyurethane flashing integrated with a pane in a flat frame measuring 47 x 47 cm. It incorporates a 4 mm toughened pane with a photoactive, easy-clean, hydrophilic coating that speeds up surface drying. This makes it much easier to keep the unit clean and therefore maintain the full efficiency of the sun tunnel.

The next element, between the roof and ceiling, is a mirrored light-transmitting tunnel. In the TWR sun tunnel it consists of two elbow sections and two tubes, each 62 cm long and 35 cm (14") in diameter. Thanks to the Miro Silver coating, light transmission efficiency is up to 98%. The standard TWR sun tunnel kit brings daylight over a distance of 1,85 metres from roof to ceiling. For greater distances, ZTR tunnel extension sections must be used. Together with the sun tunnel, these can form a tunnel up to 6 m long.

The third element, fitted to the ceiling, is an acrylic insulation kit providing effective thermal insulation. The sun tunnel comes with a matt pane as standard. A frosted or prismatic pane can be ordered as an extra. 

Sun tunnels provide a significant energy gain compared with artificial lighting. The energy obtained from natural light is approximately 9 W per 1000 lumens. For example, if the light output from the sun tunnel is 2000 lumens, the solar energy supplied is approximately 18 W. The amount of light passing through a sun tunnel depends on its construction. Thanks to its easy-clean pane and smooth mirrored tunnel, the VELUX TWR sun tunnel ensures minimal light losses: just 6% per 1 m of tunnel length and 10% per elbow that changes the direction of the tunnel. Even on a winter day, it provides an amount of light comparable to a 60 W bulb.

A ZTL electric lighting kit can also be fitted in the sun tunnel to light the room after dark. The kit can be installed after the sun tunnel has been fitted. Maximum bulb wattage: 23 W.

Construction

• Ut value = 2,2 W/m2K

• polyurethane flashing integrated with a pane in a flat frame - roof element dimensions 47 x 47 cm

• 4 mm toughened pane with an easy-clean coating

• tunnel construction: TWR - 2 elbow sections and 2 tubes, each 62 cm long, forming a rigid light-transmitting tunnel 35 cm (14") in diameter,

• acrylic insulation kit

• ceiling trim in the form of a white ring (standard)

• permitted roof pitch from 15° to 60° (profiled roofing materials) and from 35° to 60° (flat roofing materials)