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  BU579 WEERS - Window Energy Efficiency Rating System

BU579.jpgThe Window Energy Efficiency Rating System (WEERS) is a 6-star rating system for assessing the thermal performance of new residential windows. It was developed by BRANZ in conjunction with the Window Association of New Zealand (WANZ).

WEERS combines the thermal performance of the frame and glazing, together with the size of the window, to calculate an individual thermal performance rating Rw for each window.

The bulletin covers:

  • how does WEERS work
  • window specification and manufacture
  • comparing windows
  • what is not covered in WEERS
  • window Rw calculation
  • calculating a WEERS rating.

Publication date: December 2014 Keywords: aluminium, condensation, double glazing, glass, glazing, IGU, insulation, joinery, natural light, solar, sustainability, window