If your glazier has used the very latest generation of Pilks energikare glass in the installation it is a known and accepted phoenomenen, and is caused by the excellent insulating properties of the glass. It has been common in Scandanavia for many years, and is not a fault. Older types of glazing used to let residual heat pass through from inside to out, but K coated and argon filled units let a miniscule amount through, hence the condensation on the outside proving your double glazing is top notch and doing what its supposed to. Rest assured, its not a fault. Kev
Kev, October 2010
