Kristalbond is an alternative to retrofitting with double glazing. It gives you a similar U-Value (3.46) as a standard double glazed unit (4/6/4) (3.15), but KristalBond gives you the added advantage of a 99% UV block out without having to add anything to its makeup. Without the need to replace parts of the old aluminium joinery, which makes double glazing more expensive, KristalBond is becoming the new glazing alternative for people who want to become more energy efficient and are worried about the harmful UV rays that are present in New Zealand. Description Described as “The World’s New Ozone Layer”, Kristalbond is a more advanced and importantly a cheaper alternative to retrofit double glazing. Typically Kristalbond costs up to 50 percent less than double glazing and requires virtually no maintenance. With a U-Value of 3.46, an R-Value of 0.29, you can clearly see a thermal reduction from a standard 4mm piece of glass which has a U-Value of 5.88, an R-Value of 0.17. It also cuts out 99% of the damaging UV rays.