Efficiency within double glazed windows is measured by its U-Value of the entire unit, including glass. The lower the number, the more insulated the window or door.

• A typical single glazed aluminium window generally rates at about 7.0
• A typical double glazed aluminium window generally rates at about 4.5
• A typical uPVC double glazed window rates up to 1.8
• A typical uPVC triple glazed window rates 0.7

The above U-Values indicate the potential to save valuable heating and cooling energy being lost through your windows.