Impossible to tell from the little bit of information you have provided.

Depends on the window but you are talking about the difference of one additional frame spar/mullion that is probably less than 10" in total width.

Thanks for you replies.

To add more clarity, these will be dual-paned, low-e, tinted windows in a vinyl frame. They're south-facing in southern california, so we need to keep the sun out!

Is there a significant cost difference between a 6x6 ft window vs 9x6 ft window?

Also, structurally is safe to go to 9x6 ft windows? I know the glass will be tempered, so it will 4x stronger, but how safer is it compared to a 6x6 ft window.

Also, it is easier to get 6ft wide blinds vs 9ft wide blinds?

Basically, is the extra wow-factor of the 9ft wide window worth the added expense and possibly decreased safety?

Thanks!

A 9' window is more costly than a 6' window. That said, quantity will typically trump that difference, so 3) 6' units will almost certainly be more than only 2) 9' units. Tempered glass in the 9' units and not the 6' will mitigate that a bit, but I'd still expect the 3 units to be more costly than the 2... From a design perspective, that is a bit more subjective. IMO, the 2) 9' units will offer a bit more drama, while the 3) 6' units may be a little better structurally. As far as safety, the tempered will be safer in most cased despite the larger size

"Also, it is easier to get 6ft wide blinds vs 9ft wide blinds?"

My wife used to sell them. If you have a 'cellular blind" that you pull up - it'get's pretty heavy, you will have to use your hand to help them up, and there are multiple cords (4 to 6) to deal with the weight and span.

If you go horizontal - consider the 'stacking' of the blind - on each end of window.

As an engineer, I sometimes would go with my wife - and see these 'impossible' windows, where there was no space to install a blind. Make sure there is sufficient space (and perhaps blocking) to hold the blinds.

Yes, this makes sense.

I'm thinking of using a motorized solar blind, if it isn't too expensive.

Make sure you have electrical outlets installed near the top of the window.

Im not sure about wind load or DP ratings where you are but a vinyl window over 154 united inches wont perform well if you get high winds it could be a problem..the frames are hollow and the glass weighs alot in a 9x6. That would be my concern..the glass could fail quicker maybe not who knows..just something to think about

Definitely something to be concerned about!

We don't really get hurricane level winds here, but I'll ask the Architect.

Some of the European PVC profiles are steel reinforced and will maintain a sufficient DP rating at that size. The companies that fabricate tilt and turn windows from extruders like Veka would be able to produce this. I checked to see if Simonton would make the window that size and the largest they produce is 96" x 72" but even with their hollow frame the DP rating is LC45 in that size. Not too bad for a window of that size.

+1. I would not get into overgeneralizing this situation by looking only at the material. Every product is engineered differently, so I'd look at them each on their individual merit.