Cost - Depends. Around $15m2 for the actual roof. Raking ceilings it depends on a lot of factors. I wouldn't do it on dog box 3x2's more for the higher spec building.
A/C - Not really an issue. Clever use of bulkheads and such get the job done. Maybe put raking in main areas and master suite...
Double glazing is thankfully becoming more common and therefore more affordable. 6 star minimum energy efficiency is a step in the right direction. The next part is to utilise roof space temperatures more (when they are completely insulated with anticon and ceilings) and minimise the use of...
