TERMOLUX is a special insulating glass that scatters light and reflects sun rays. It is composed of at least two glass panes with an interlayer of spun glass between them. The fibres of the spun glass lie on top of each other at specific angles to give a high-light scatter effect.

TERMOLUX is hermetically sealed around the edges by an organic sealant against outside influences. It is therefore impossible to cut or shape TERMOLUX panes.



TERMOLUX is a diffusing and insulating glazing that reflects the sun rays. Its foremost characteristic is diffusion, an effect which is stronger when the sun shines. As with all diffusing glasses, workplaces should therefore be arranged in such a way that sunlit panes are not in the centre of the visual field. A 3 mm spun glass is recommended for sports halls, where freedom from glare is wanted. As a roof glazing, TERMOLUX protects the interior against excessive solar radiation. Roof lights glazed with TERMOLUX produce, in addition to a completely uniform light diffusion, an excellent in-depth interior illumination due to the additional reflection from interior ceiling.

TERMOLUX creates north light conditions irrespective of its orientation, and its neutral light prevents shifts in colours. Because of its very good colour rendering index, TERMOLUX is often used in museums and exhibitions, printing works, fashion houses, and also schools and sports halls.



For the glazing installation, the same guidelines and standards apply as for all insulating glasses. For glazing under compression stress, the load must be equally distributed over all four sides, just as a load distributed over length. As far as dry glazing is concerned, it is recommended to contact the manufacturer.


Physical properties

Thermical properties

The heat transmission factor U is 3.8 W/m2K for TERMOLUX with 2 x float 4 mm and a 1.5 mm spun glass layer, this being a substantial improvement over simple glazing. TERMOLUX COMBI gives values from 2.2 to 0.7 W/m2K, a considerable improvement over ordinary insulated glazing.


Total energy transmission

The total energy transmission factor g for TERMOLUX with 2 x float 4 mm and a 1.5 mm spun glass layer is equal to 44 %. These are extremely good values if one considers that for 4 mm float glass alone the factor g is 87 %. By using special combinations, g values under 20 % can be obtained.


Acoustic properties

According to measurements made by the Swiss Materials Testing Laboratory EMPA, the airborne sound insulation factor Rw of TERMOLUX 2 x 4 mm with 1.5 mm spun glass fibres is 32 dB, and with 3 mm spun glass it is 34 dB.


Optical properties

TERMOLUX offers a glare-free and shadow-free diffused light which is pleasant to the eye and is constant regardless of the angle of incidence. TERMOLUX always gives the same conditions as if the light came from the north, independently of its actual orientation. This gives a feeling of lightness which is not measurable but has an apparent effect far superior to the light transmission factor of 46 % for TERMOLUX from 2 x float 4 mm with 1.5 mm spun glass and 27 % with 3 mm spun glass.


Light properties

When falling on or passing through any material or building part, light undergoes a change. This change can be described quantitatively by means of various coefficients, making it possible to precisely characterize any material or building part. The light transmission factor characterizes the light transmission of a body or a building part, but says nothing about the distribution of light. The half-value angle determines the direction from which the intensity of the transmitted light is equal to half the intensity at a right angle to the building part, and is therefore suitable for determining the diffusion of light. The very high value of TERMOLUX with 47° illustrate the very good light diffusion that results from the spun glass. TERMOLUX is absolutely stable to light and cannot become yellow, since the intermediate layer is made from spun glass. It also offers protection from ultra-violet rays for objects placed behind it.

Spun glass 1,5 mm Thickness (mm) Weight (kg/m²) Max. dimensions (cm) U value (W/m²K) Light transmission (T) Half-value angle (Y) Total energy trans./Sun Factor (g/F.S.) Sound insulation (dB)
2 x 4 mm 9 - 10 23 120 x 250 3.8 49 47 47 32
2 x 6 mm 13 - 14 33 180 x 300 3.8 48 48 45 34
2 x 4 mm Spun glass 3 mm 11 - 12 25 120 x 250 3.4 32 53 33 34
1 x wire glass 6 - 7 mm 12 - 13 31 85 x 400 3.5 30 38 31 34