If you buy a car or a computer, you can read the reviews and even try before you buy. But unfortunately, it’s hard to do the same with window joinery. Once it’s installed, you have to hope that it will do the job . . . unless it wears the NZS 4211 label.
There’s a strict quality standard for windows and doors in New Zealand: it’s called NZS 4211:2008 Specification for Performance of Windows. The New Zealand Building Code, clause E2/VM1, 1.2c, requires that window and door units be manufactured and tested to NZS 4211 to the relevant wind zone. Only windows and doors that comply with the standard will comply with the New Zealand Building Code.
All Window & Glass Association New Zealand members manufacture and test their units to the standards and performance required by NZS 4211:2008.
All windows carrying the NZS 4211 label have been rigorously tested in an accredited laboratory. They’re tested against a whole range of performance criteria, including air leakage, water leakage, and deflection under wind pressure.
NZS 4211 requires that all window manufacturers label each and every window and door unit they make. If a unit is NOT labelled, it does NOT comply with the standard.
Not every window passes. But if it does, it will carry the NZS 4211 label, which shows you the brand name of the window, which wind zone it is designed for, and its air leakage grade (‘LEVEL’). The label also carries a Window & Glass Association New Zealand logo. This gives you assurance that it’s strong enough to withstand the rigours of the New Zealand climate.
Window & Glass Association New Zealand strongly supports building inspectors rejecting any window or door that is not labelled with the required compliance information.
Each opening window unit should be labelled in the stay cavity, immediately below the left-hand side stay. Doors should be labelled on the door jamb immediately below the top hinge. Fixed lites should be labelled on the top right-hand corner of the unit (viewed from the inside of the building).
For commercial units, the label should appear as per windows and doors above whenever possible, otherwise fixed on the bottom right-hand corner of the unit (viewed from the inside of the building). Commercial entranceways require specific design, case by case.
Most of New Zealand’s reputable manufacturers belong to the Window & Glass Association New Zealand. They know their products will be tested, and they are happy to put them to the test. So the next time you are thinking about buying windows and doors, check you are dealing with a Window & Glass Association New Zealand member. You will then be assured of compliance with NZS 4211 and the New Zealand Building Code.
Window performance standards from other countries cannot be accepted without a registered window engineer’s report validating each design and its suitability for specific wind zones within New Zealand.