By strictly following passive solar design guidelines, it is not too hard to design a very comfortable five star home. HOWEVER, in the real world, there can be fabulous views to the west, big beautiful shade trees in the north and a whole host of other site limitations. NatHERS software can easily show what measures are most effective in getting around these problems by showing the relative difference changing windows, walls, insulation etc makes.

In NSW, 51 councils to date require a National Home Energy Rating Scheme rating, now or soon, usually of 3 1/2 stars or more. All applications to HIA competitions also require NatHERS ratings.