What is Pilkington K Glass and how does it work?
The glass in your windows absorbs heat then radiates it again on the colder, outside surface. Pilkington K Glass has what is called a low emissivity coating on the surface that faces into the air gap of the double glazing unit. Low emissivity means the coating is a poor radiator. The heat absorbed by the coated glass is inhibited from radiating across the air gap and then from the outer pane to the cold outside world. Instead the heat is reflected back into the room by the coating. It works in a similar way to a sheet of reflecting foil placed behind a central heating radiator which, as you know, bounces the heat back into the room. Heat losses through different materials can be compared by their “U values”. The higher the U value, the greater the heat loss through the material. The U value of a single pane window is 5.6. Double glazing with ordinary glass has a U value of 2.8. Double glazing with Pilkington K Glass has a U value of only 1.9, considerably better than conventional doubl
