How WERS Works

WERS uses computer simulation, based on real data gathered in scientific testing, to reflect the changes in performance in the key areas of heating, cooling and fading.

It's these computer results which are translated to a generic star rating system, within given bands of performance, to allow you to evaluate the cost and benefit implications of various frame and glass combinations.

The figures relate to an average New Zealand house, within one of three defined climatic zones. The average house has 20 windows and doors.

An accredited simulator, a person form an independent agency qualified to test the window systems, certifies the star ratings.

How to use WERS

When asking for a price for your windows and doors, ask  the supplier for a WERS star rating for the different options you are considering.

You can then consider the ratings in conjunction with price estimates.

This information will enable you to choose different options for different parts of your house. Or perhaps you might wish to change glass type of the sunny side, for example to reduce fading.

Once you have decided on glass and frame types the supplier can offer you a quotation.

How to recognise WERS

A rating certificate and a schedule outlining the star rating for each individual window type will be issued on request with your supplier's final invoice.

It will set out a licence number and the star rating for cooling, heating and fading.

The certificate will include a brief description of the makeup of the window or door, so you know the information is accurate.

When you receiver the glazed units, a branded label will be attached verifying a WERS rated product.