The association of European Polycarbonate Sheet Extruders (EPSE, Brussels / Belgium; www.epse.org) has begun a campagne to promote the use of corrugated PC sheets for greenhouse roofs and multi-wall sheets for greenhouse walls. This will help achieve a balance of thermal insulation and light transmission, the association says.

Corrugated polycarbonate sheets provide around 90% light transmission but no thermal insulation, while multi-wall sheets provide approximately 80% light transmission with good thermal insulation, EPSE says.

When installed on a roof, corrugated sheets maximise natural daylight in the greenhouse. The lack of thermal insulation becomes a benefit as the heat loss through the roof prevents snow from accumulating during winter, EPSE said. In addition, the benefits of greenhouse walls made out of multiwall PC sheets are high light transmission to the interior of the greenhouse and good thermal insulation that allows for reduction in heating costs in the winter.