Good quality windows and doors deserve a good quality window installation.  And that means they should be installed recessed into your wall; not hung out over the cladding as is so commonly done! In other words, the warm barrier down the middle of the glass and down the middle of

A good R-value for a window in New Zealand is R0.65 to R0.8. You can achieve this with: How do I know the R-value for my windows? The R-values of windows are made up of two important factors, both of which you can ask to change or specify. (Also note