Home The New Zealand Window Efficiency Rating System

The Window Efficiency Rating Scheme (WERS) is the official, independent system of the New Zealand window industry comparing the effectiveness of your windows and glass doors.

The systems shows you how most of the common glass and frame types perform in terms of heating, cooling and fading.

HEATING the cost of keeping a home warm in winter

COOLING the cost of keeping a home cool in summer

CONDENSATION effectiveness in reducing condensation

FADING the impact on carpets and furnishings of the sun coming through windows

You can find out more about the WERS on the Metroglass website.

The Window Efficiency Rating System (WERS) has been a rating system promoted by the glazing industry some years ago.

With the advances of window technology with new frame and glass types the WERS system lost most of its relevance and has therefore been removed from the Design Navigator website.

You can access an extensive set of window R-values in the Design Navigator H1 calculator at the bottom of the wall and windows data entry page. These R-values have been aligned with the window R-values shown in Clause H1 Edition 5 (2021).