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Pilkington K Glass - position in a unit

Pilkington K Glass is a low emissivity glass, specifically designed to enhance the thermal insulation of insulating units. It achieves this by being positioned in the insulating unit with the Pilkington K Glass coating on a surface facing the cavity.

In a double glazing unit, counting the surfaces from the exterior of the building, the Pilkington K Glass coating should be on surface 2 (the inner surface of the outer pane), or surface 3 (the cavity surface of the inner pane).

Pilkington K Glass performs the function of enhancing the thermal insulation (reducing the U value) equally well whether it is positioned on surface 2 or surface 3. However, with any coated glass, there may be slight optical effects when the coating is present. These optical effects are reduced when Pilkington K Glass is used with the coating on surface 3, rather than surface 2.

General advice is that the preferred location of the Pilkington K Glass coating is on surface 3 of the unit, but if the glass types used in the unit make it difficult to assemble the unit with the Pilkington K Glass coating on surface 3, then no loss of thermal performance is suffered by using it on surface 2. In particular, when Pilkington K Glass is used with Pilkington Texture glass, where the Pilkington Texture glass is normally installed as the inner pane of a double glazing unit, the Pilkington K Glass should be installed with its coating on surface 2. Any slight optical effects will be masked by the presence of the Pilkington Texture glass.