Keep them square or rectangular stay away from shapes especially round tops the price for them will be allot

Generally the most dramatic increase on double or triple pane windows comes once the height and width exceed 101 inches. This measurement is referred to as united inches or UI. Most installers charge more due to increased weight which can require another installer and most manufacturers charge more due to the increased structural requirements.

guessing the 101" is a height + width? which kinda makes sense --- 3'x5' window 36"x60"=96...so my cathedral ones are going to set me back quite a bit...

I suspect you are going to have a very difficult time finding a 16' window. most manufacturers will not make anything over 96" and many will not make one over 84". You would have to go with a comercial grade aluminum to get those sizes.

I would consider multiple windows maybe an awning window under a picture window with some kind of geometric on top would look really nice. This is not a project where you would be advised to cut corners or purchase anything but top quality windows.

+1

Probably going to be easiest to skin this window "cat" with a mulled unit.

I am doing a house with a view and 6x6 was my limit (well it happened to be the manufacturers limit). We are doing 6 picture windows - the base is a 4x6, 6x6, 4x6; and then there are 2 ft high transoms over that - this gives 8 feet of window on a 10 ft ceiling. There are packs of studs in between.

We have mulled units in our primary house. 4 30 inch wide DH windows mulled together. Makes for a 10 ft wide window. They are 6 feet tall with another 1 foot of transom on top - all this is on an 11 ft ceiling.

There are so many pricing points, one of which are the tempered glass rules. The tempered glass rules have to do with over 9 sq feet (among other things). Keeping your DH windows to 30 inches wide x 6 feet tall keeps you under the 9 feet cutoff. There is a point (24sqft?) where everything is tempered anyway.

Different manufacturers differ considerably. First decision is what windows do you want to be operable? Next is material (vinyl, wood etc)?

I once had a 2 story great room and it was a tract house. So cost was paramount. It had windows up about 12 feet (on probably a 18 ft wall). There were 6x6 fixed flanked by 3x6 DH.s on either side with stud packs in between. Then about 2 feet up were matching transoms 2-3 feet high. So the windows weren't the whole way up the wall but they were substantial. It was a good amount of operable window, made for a dramatic wall at a reasonable price point.

Prices sometimes are strange. Picture windows are often more expensive than double hung but not always. My current house has a ton of DHs because they were the cheapest option. I think casement was $100 over DH with picture being $15 less than casement (for 30x60 window).

The last thing to consider is structural issues on the wall. If there is a lot of window, then there is not a lot of stregnth to the wall. Our garage wall (3 car - a double door and a single door) had to be built out of 2x8s and then sheathed on both sides with OSB for strength. This code was fairly new as our neighbors with a 4 year old house have more normal garage walls. This is something to address with local structural engineers and absolutely depends on local codes.

thanks for the additional info...