You need to figure out what type of material you want, what the existing construction is, any exterior considerations (rot, trim, etc), and what window arrangement you want to go with.

A full tear out of those window will allow you the ability to tweak and change the layout however you might want.

I have no idea what I want or even whats out there. I understand that I will have to do a full tear out, but I figured using the same layout would be the most cost effective or is that wrong considereing they might be custom sized? As for the current windows, I know the exterior trim is aluminum, and the inside trim I think is also.

You need to get out and look at some windows. We can't tell you what to by as that is an individual decision. We can help you pick a good window once you decide if you want wood, vinyl, cladded wood, aluminum, fiberglass or a composite. Call a few companies and have them come out and show you some windows.

"From the pic below it is very clear that these windows will need to be replaced at some point."

Why?

They appear to be custom windows that will be expensive to replace.

If they are rotted or leaking that might be an option though.
Just because they are old is not a reason to replace them

Decide first whether a wall of windows is the look you want to keep. It does seem to suit the house and the space. But besides aesthetics, it may also impact heating/cooling, security, and furnishing flexibility. And window coverings.

Then you should definitely shop, or maybe look at some books, to get an idea of what is involved in window replacement. If they do not need to be done urgently, as a veteran home renovator I would recommend you live with them first. You will learn what your needs are in the space, and learn more what is really important to you about the windows, whether they should open and if so how, where you want the divisions, and so on.

Understanding exactly what the problem is will also help you to make the most economical decision - you may not need to replace the whole thing.

Off topic, is that a colonial light fixture with hats? What a relic! We just bought one and installed it :-)
But we prefer it hat-less.

Karin L

If you didn't tell me they were aluminum, I would say they look like Andersen Beauty Line windows from the 60s.

I have no doubt that these were high end or even custom windows of their time. The issue is that they are original from the late 50's and they are very drafy, some are even cracked or dont open. Thank you all for your input. I will definitely do more research. What I do know is that I want to keep the size the same. These massive windows were a huge selling point for us.

One thing I could tell you, which probably seems blindingly obvious to everyone else but I had to figure it out the hard way as we conceptualized and bought some replacement windows, is that the amount of daylight you will end up with depends primarily on the material you choose, and whether you make the panes openable or not.

Aluminum will give you the greatest window surface, while vinyl and wood need more space for the frame. Any window that is a fixed pane will give you the most daylight for that opening, but if you make it an openable window, you double up on the amount of frame you need.

Here is a photo of our new window, just to illustrate. It is a wood window with all openable glass. It replaced a large fixed pane aluminum window with just a small sliding opening at the bottom. Previously, therefore, the opening was virtually all glass. Now we have lost several inches in all directions, so we did lose a lot of light. However, being able to open different parts for different purposes is an absolute gift, so we judged the loss of light to be a small price to pay. Incidentally, since you were asking about price, this was a custom-built window that cost us circa $3000 (Canadian).

So I would guess that you want to look at aluminum to maximize glass surface and minimize the effect of the cross bars.

Karin L

Thank Your Karin, I had not even thought of the fact that the different window frame materials will affect the amount of light. In my amateur mind, a window has always just been a window. That is partially why I feel so lost.