Glazing can be a high area of heat loss from a property. This can be reduced wth the installation of double or triple glazing. This type of glazing uses 2 or 3 layers of thin glass with a cavity.

The elements affecting a window's performance include:

• No. of Glass Layers (more is better)
• The Cavity Width (increasing this will reduce the heat loss)
• The Gas in the Cavity (argon and krypton are better than air)
• Spacer Bars (foam loses less heat than aluminium)
• Low Emmisivity Coating (this reduces the heat loss due to radiation)
• Thermal Breaks in the Frame
• The Frame Material (wood and plastic lose less heat then aluminium)

Currently most double glazed windows have a U-value of 1.7, which is quite good.