According to a recent article in ‘The Conversation’, some builders are said to use the star rating system in a way that could mislead customers. The same can be said of the window industry. If you are looking for highly energy efficient windows, do not believe claims such as ‘best energy efficient windows in Australia’, if the claim cannot be independently proven.

WERS – Window Energy Rating Scheme – is the Australian rating system that gives windows stars for cooling and for heating. It also rates windows for their U-value and air infiltration. The lower the U-value, the higher the energy efficiency of the window; similarly, when the air infiltration is low, the drafts will be reduced, making the window more energy efficient.

It is easy to verify someone’s claims by visiting the WERS website and searching for the company’s name in ‘certified products’.

Paarhammer has been a member of WERS for many years, and has their windows tested and the results listed on the WERS website. The public can easily see that the claims we make about our products are substantiated. In addition, Paarhammer is audited every year by an independent auditor who comes to the factory, takes a window from somewhere in the manufacturing process, and conducts a check to ensure that products are manufactured precisely to the original approved and tested design.

We all know stars and star ratings from whitegoods - they are also used for houses and components of the build, such as windows. A house must have as its minimum a six-star rating but to be more energy efficient, a star rating above six is advisable. Every additional house star above six increases the energy efficiency of the house by 30%.

Paarhammer products achieve up to 7 ½ WERS stars and up to 85% energy efficiency. Please see The latest Wood-Alu range has been tested but has not yet been added to the ratings on the WERS website. If you would like to see these ratings, please download the Architectural and Product Information Book from Paarhammer.

So, the next time you see slogans such as ‘best energy efficient windows Australia,’ know that this is only a marketing slogan unless it can be verified through independent ratings.

For all your window and door enquiries, please visit