Windows rated for energy efficiency

A new window rating system has made it easier for New Zealanders building a house to choose energy efficient windows.

The Window Energy Efficiency Rating System – WEERS – was developed by the Building Research Association of New Zealand (BRANZ) in conjunction with the Window Association of New Zealand (WANZ).

It is supported by Government agencies EECA (Energy Efficiency Conservation Authority) and the Foundation for Research, Science and Technology.

With WEERS, consumers can balance cost and energy efficiency without compromising other important technical matters, satisfying the requirements of the New Zealand Building Code and meeting specific energy targets.

WEERS offers an accurate rating specific to each window and door purchased based on the materials used (frame, glass and associated components).

The ratings are specific to New Zealand climatic conditions.

WANZ-registered window manufacturer will be able to provide customers with an R value for the entire houselot, which can be given to the architect or energy consultant to use in whole-house energy calculations.

The WEERS certificate carries the familiar six-star rating system, records the R value of each window and the Energy Star Mark, if it meets the requirements of EECA’s programme.

● Before being WEERS rated, windows and doors must meet the WANZ requirements which include compliance with the New Zealand Building Code including B1 Structure, B2 Durability, and E2 External Moisture; NZS4211 Specification for the Performance of Windows; NZS4223 for glass selection and glazing, and IGUMA-EN1279 for testing insulating glass units.