Glossary of Window and Door Terms

A secure locking mechanism used to hold a window panel marginally open for the benefit of ventiallation.

Visible Transmittance (VT) refers to the amount of visible light which can pass through a piece of glass. The VT of a piece of glass is represented as a number between 0 and 1 – the higher the number the more light which can be transmitted through a pane. The VT of a pane of glass can be altered by things like the type of glazing, and any coatings on the glass (such as tinting).

Weather stripping refers to material which is placed over the openings, ventings or cracks of window and door units to prevent air and water coming through. Weather stripping helps to make your windows and doors more energy efficient, as it prevents cool air escaping the house in summer, and warm air escaping the house in winter.

WERS refers to the Windows Energy Rating Scheme. WERS is a system developed by the Australian Window Association (AWA) and measures how energy efficient windows are, based on their cooling and heating performance. Both a window’s heating and cooling performance are individually rated with a star rating system on a scale of 0 to 10 stars – the more stars, the better the energy efficiency of the window. Windows that have been rated will display the WERS logo.