Glass vs. polycarbonate
In the past, the most popular shape for skylights was a pyramid or a ridge. The frame was made of welded steel profiles and filled with reinforced glass panes. The construction was then plugged with putty. With time, however, and under the influence of weather conditions, the plugging would dilapidate and the glass panes would crack, which would cause leaks and heat losses.
The best alternative for the traditional skylights are Eskade-System barrel vault skylights. They are made of aluminum profiles filled with state-of-the-art light cellular polycarbonate sheets and plugged with EPDM gaskets. The construction is very durable and rid of the drawbacks of steel and glass skylights.
Old-fashioned ridge skylights (before replacing)
Light, modern, polycarbonate barrel vault skylights
Thermal properties of polycarbonate skylights
The average surface temperature of a traditional glass skylight is ca 12 degrees Celsius. The white shades on the picture indicate the temperature of 14-16 degrees and display the cracks on the reinforced glass; the brighter spot at the back is the ventilation aperture.
The average temperature on the surface of a polycarbonate skylight is ca 6 degrees Celsius. The aluminum profiles have the highest temperature of all the elements of the skylight construction. The pictures show how regular the profile of temperature is for continuous skylights.
The photos above show a comparison between two different skylight constructions. They were taken during the measuring of the
surface temperature by a thermal vision camera, which gives very accurate results. The temperature of the surroundings was
approximately 1 degree Celsius and was the same for both instances of measurement, which allowed us to gather plausible data for comparison
It turns out that the differences between glass and polycarbonate skylights in terms of thermal insulation are vast.
The heat transfer coefficient of cellular PC sheets is 2,5 times better than that of reinforced glass.
Moreover, the properties of polycarbonate allow for it to be shaped into an arch or a vault, which minimizes
the surface of cooling without bearing a negative effect on the durability of the construction. Compared to
ridge skylights, vault skylights have 29% less surface. In the case of big industrial buildings, such economy of surface entails much lower heating costs.