Hi All
Just by way of information for the technically oriented...
There are 2 sets of energy rating data (U values) for all windows, ANAC and NFRC. Currently, NFRC is in WERS, ANAC is in FirstRate (& BERS etc..), these U values vary by up to 30% (NFRC being worse).
What is the difference between ANAC and NFRC ratings?
The ANAC ratings have been available for many years and are based on "Australian National Average Conditions". This rating system is being replaced by a more advanced and globally acknowledged system developed by the NFRC (National Fenestration Rating Council) in the USA. Unfortunately, the building code called for its use before the "whole of house" rating software (called Accurate - for use in First Rate, BASIX, BERS, etc) was updated. The result is that there are two options available until the transition is complete. Companies can continue with ANAC ratings, and for those with NFRC ratings, as an interim measure, these have been adjusted so that they may run in the "whole of house" software packages. These will be re-rated again when the Accurate software upgrade has been completed, and the ANAC ratings will be discontinued.
Houses that rate today as 5 star in FirstRate (& others) will not rate so well when the NFRC ratings replace ANAC in the near future.