Refers to the reduction of the thermal bridging effect around the perimeter of double-glazed units by replacing the conventional aluminium cavity spacerbar with a low heat-conductive thermally insulating cavity spacer.

A single figure rating for the sound insulation of building elements. Includes a weighting for the human ear and measures actual sound transmittance.

The pressure, positive or negative, acting on an external surface of a building caused by the direct action of the wind. Commonly expressed as N/m2.

A scheme launched in 2004 by the British Fenestration Rating Council (BFRC), to assess the whole window energy performance of a window including all the components that make up the window.