Louvre window. Good for ventilation. Ideal for a bathroom. Yes, they look great. Can be expensive when compared to others but these are overall a very good window configuration. Try 'Breezeway' for suppliers in your area.

Thank you dohraime. I like you hypothesis about step feature at the gable front and art deco era. I think that was probably the closest this I could find at this stage in terms of visual similarity. The living area connected to the kitchen was extended back probably around 70s-80s. As far as we know, the Italian gentleman had a big family with four kids, so he needed more space for beds. The other two rooms at the front may have been renovated at some point as well. Cornices in the front three rooms including hall way definitely look more elaborate than one in the extension area. We have only three windows left to us that was from the era of original owners. They were time double hung windows that were very old, very fragile, and difficult to open. These three were at the two front rooms and a kitchen as pictured in 2010 and 2014 sales. As far as I can see from the old pictures of 2010 sales, windows in the extension living room were double hung windows of the same style as well. So they may have been replaced at some point in time. Previous owner replaced most of the windows to double glazed units, and we completed the remaining three after moving in last year.

I want some decorative, ornamental only, window shutters for either side of three windows. Anyone know where in Melbourne might I purchase them

Colonial panes looks awful on sliding windows. They look best on double hung. What I don't really get is why you'd want to build an American-styled home in a state known for it's vernacular architecture which is very similar in appeal? Hamptons/Qlder are almost the same thing but one will look authentic in QLD and the other not so much. This house is sitting in a hot state and yet it has almost no eaves, limited deep verandahs. That style is built for a temperate climate (the USA shares practically no climate similarities with Australia except in Florida). So the owners opted for the climatically different house and put it in the one state where the vernacular would actually function better. It would have been a simple thing to Hamptoms style a Qlder and benefit from both.