SECONDARY GLAZING

In some cases, for example in historic buildings where the external appearance cannot be altered, it is not possible to replace old single glazed windows with new double glazed units. In this case, secondary glazing may be the answer. Secondary glazing can improve the thermal performance of single glazed windows by up to 50%. Additional window frames, usually aluminium (but sometimes plastic) are fixed on the inside of the existing windows. Secondary glazing will also improve acoustic insulation, reducing aircraft and traffic noise (but only when the windows are closed!). Secondary glazing needs to be carefully designed so that windows can be cleaned and opened and so that the glazing bars do not obstruct the visual aspect of the main window. Some secondary glazing can be removed in summer months (this is common in old houses in Scandinavia), but care has to be taken to avoid breakage and injury during storage.