I believe double glazing is now standard on new build in Tasmania but rare anywhere else. The builder did take a sharp intake of breath when we asked for it and said it would be very expensive - in the end after a bit of research he came back with an option of a slightly different design of window that wasn't much more costly at all, considering the benefits. Most houses are built to the basic standards though so beware.
As the cost of energy has risen more people are becoming aware of the economic values of better insulation. I was amazed at how few solar panels there were in SA compared to Lancashire!