Double Glazing
Insulating windows are usually double paned and are also referred to as "double glazing" but windows with triple panes or more, "triple glazing" are sometimes seen in very cold areas. Insulated glazing is framed in a sash or frame as if it were a very thick piece of glass.
By trapping air between two panes of glass, double-glazing creates an insulating barrier that reduces heat loss, noise and condensation.
Double-glazed windows come in a variety of styles but it's worth checking any restrictions on your house due to age and location. Fitting double-glazing when your existing window frames need replacing will save you time and money.
Energy Efficient glazing?
Energy efficient glazing contains more than one pane of glass, with air gaps between each pane. It includes double, triple and even quadruple glazing. The air gap between each pane can be filled with gases, such as argon, that help reduce heat loss. Some windows may also have a special coating that decrases heat loss through the window and increases heat gain from the sun.The heat and sound insulation of glazing may also be improved through the use of a film or coating applied to its surface. This film is typically made of polyester or metal, and may give a reflective appearance and one-way mirror effect to the window, and may improve both heat and sound insulation. This may be used on single-glazed windows as an alternative to insulated glazing, or on the outside layer of insulated glazing to further improve its effectiveness. Such coatings may reduce fading of fabric and improve safety in the case of breakage.
Secondary glazing is sometimes used as a cheaper alternative. This consists of a layer of glazing placed retrofitted inside the window, to provide sound and heat insulation. Plastic sheet may be used for heat insulation, but may only last for one season