mattwnz:These PVC windows have apparently been tested with Branz for UV http://homerit.co.nz/why-choose-homerit/branz-appraised/ . It does say that low quality, low UV stable PVC-U profiles may discolor and become brittle in several years’ time. So it pays to check that the UV rating on them.
Would highly recommend their BRANZ endorsed premium brand,
We ordered through these guys, I even took a flight up to Auckland to see their factory. We ordered lots of windows and a 4m sliding stacker, with double glazed Argon glass and we are very happy with insulation and noise (we live next to main trunk train line).
The two best features for me, easy cleaning/maintenance, and no condensation on the frames unlike aluminum.
The outside looks just like our wooden windows, both have a thick white frame. From 10m back they look like our wood windows.