Even though the windows over are wonderful, the back pocket will feel the cost as they would be custom made, more expensive for the builders to install, but if casements, (open at side) that would make for great windows which catch the breezes, why anyone would want fixed windows is beyond me, the more we can open up a house and naturally ventilate it, the less you have to spend on air con, two angled windows need to be fixed. Any hot air over the opening part will sit in the ceiling space, but if you wanted to be even smarter, then i would consider the roof windows, which pivot and let the house ventilate totally, also like the cost comment with the windows over, these are expensive by it looks like you have the pitched ceiling inside, which would allow for the roof windows.

1/ at the old place we had similar configuration to your drawing..the cooktop where that is and 2 slim windows on either side. 2/ wash up like drawing is preferred as can talk or watch TV. So sink inside 3/ wall oven and microwave on top at end below is photo of our old kitchen

To Australian Home Designer. Thank you for your advice but I'm not trying to replace the doors with a window. The double glass doors are on the study, and they open onto the very small balcony which measures approx 2M X 0.9M. The balcony has slate type tiles on the floor, there is a roof above and it is enclosed either side by concrete? walls. The balcony has an opening about 2 M wide by 1.5 high, which is what I'm trying to addres. The balcony is next to useless as it is and I could make more use of it if I could enclose it. I tried to add another photo to give a better idea, but for some reason I wasn't able to. So, I'm not trying to replace a window but install something in an open space to act like a window. As this area is considered common property (even though no one else can have access to it unless they walk through the apartment), I have to advise the corporate body. Chances are they'll ask for me to arrange for a by-law to be drawn up. It never ends does it? The other thing I should mention is that Council said (when I first approached them) that the developer would have used every available space to the enth degree. The developer has confirmed this with me. The block is almost 2 years old and all owners are the first occupants. Thank you for taking the time to respond. It is much appreciated.

yes...but windows need to suit the room inside, orientation and outlook and looking at your photo you may find that it's more cost effective to remove three small windows and replace with one big window that may be all sliding or have sections of fixed glass and sections of awnings or double hung windows either horizontally or vertically...but do you need every window in the original size and location? ..take photos from every side of your house and make a numbered list of the sizes of all the existing windows and you can discuss with a window supplier to get an idea of costs BUT windows are such a vital feature of passive solar design that you should take this opportunity to rethink every window....does every window suit the purpose, are some windows too big, too hot inside, in the wrong location, not private, missing a good view or cooling breeze...check yourhome.gov.au for advice to get the best results for such a major investment and you will need skilled help to remove and install so also time to consult a builder