You can use taller windows, Andersen window as an example an A-Series window can be up to 8' tall and a 400-series can be 7'8" tall. Custom sizes also available but the cost can triple because you start dealing with reinforced frames, tempered glass, etc.

Check with different window manufacturers and see what they offer and what style window you looking for and what your options are.

Without seeing the elevations of the home it is impossible to tell fro sure but you can certainly go taller with windows. Or use seperate opening and transoms to help alleviate some of the reinforced frame necessity.

Thank You both for the replies. I will look into the taller windows. Another option is for us to just lower the ceiling height to 10’ but we really wanted the tall ceilings throughout the living area.

Our great room is 40x28 with 10' ceiling with a drop over the kitchen at one end. Four spaced 44x92" south facing windows(northern home) nearly to the floor with a roof overhang to block summer sun. Winter sun goes all the way across the room. 12' ceilings could work with a larger space. Your windows depend on the view, northern or southern home location and home orientation.

Increase the scale. Otherwise it will look odd. Depending on the style of your house - 12' may be gross overkill

I have 12' ceilings throughout my home. Interior doors are 8'. The exterior doors 8' doors with transoms above for a 10' total. The windows that are not floor length are 80". If you really want 12' ceilings, you will have to make everything much larger to make the scale work.

It totally depends on the style of your home.

Have you considered simply using fixed glazing in combination with operable lower or upper awniing windows of the same width?

Reduce the ceiling height and alleviate a lot of expensive problems. Like the 100K worth of stacked cabinets to the ceiling in the kitchen. And the huge cost of the finestration. And the ongoing cost and continual struggle to heat and cool that volume.

I am already getting 8ft doors so that is not an issue.

i would like to avoid transoms, might as well increase the window height if I were going to put transoms in, unless transoms will save money

Lower the ceiling.

What some folks are telling you is that 12-foot ceiling create more issues than simply windows on the exterior walls.

For example, how will you handle upper cabinets in the kitchen?

You don’t need 12’ walls for tall ceilings. We did 10’ walls with 8’ doors, 6’ windows and then vaulted the ceilings where we wanted them to be taller. you can fancy the vaults up to make them really add to the room. Or add geometric contrast with a double vault. I agree with Sophie and Virgil on the kitchen ceiling height.

I've owned historic homes with as much as 14' ceilings. Do a quick calculation on the total volume of the structure using the varying heights. On top of the additional cost of materials, you will discover that the HVAC costs will be huge. The cabinet costs are daunting, too.

I would suggest that 10' is a good number. You can still get the volume feel with taller doors, but no so huge that the costs go haywire. If you want to vault a great room that would create that spacious volume without having to make the entire house a jumbo.