R310.2.3 Window Wells.

The horizontal area of the window well shall be not less than 9 square feet (0.9 m2), with a horizontal projection and width of not less than 36 inches (914 mm). The area of the window well shall allow the emergency escape and rescue opening to be fully opened.

Exception: The ladder or steps required by Section R310.2.3.1 shall be permitted to encroach not more than 6 inches (152 mm) into the required dimensions of the window well.

R310.2.3.1 Ladder and steps.

Window wells with a vertical depth greater than 44 inches (1118 mm) shall be equipped with a permanently affixed ladder or steps usable with the window in the fully open position. Ladders or steps required by this section shall not be required to comply with Sections R311.7 and R311.8. Ladders or rungs shall have an inside width of not less than 12 inches (305 mm), shall project not less than 3 inches (76 mm) from the wall, and shall be spaced not more than 18 inches (457 mm) on center vertically for the full height of the window well.

Are you saying the suite is a "studio," meaning no defining walls in the space, and only the 1 limited exterior wall? Because if it has a separate bedroom then that is where the emergency escape & rescue window needs to be located, would that help with allowing a smaller window(s) in the living area?

In addition, the window well is quite large and deep to follow the code listed by GN above, and there are versions that terrace out (for the "ladder") to around 60" deep, like this one:

Also, it may not help with no available wall space, but just to note if it provides you with another option for more light an emergency escape & rescue opening does not have to be a window, it can be a door.

Thanks. Yes, it's a studio of sorts, if you don't count her little sewing room, just for my mom. Of the 3 walls in the large room, one is under the porch and the other is under the deck. That leaves one wall to work with. We have a separate entrance to the basement from the garage, so she does have 2 exits. Maximum light is our concern. It's kind of a dungeon down there now. We've had a couple of companies out. Interestingly, the first one said we could fit 2 egress-sized wells on the wall, and the second said no we couldn't, the second window would need to be much smaller. He was the owner, not a salesman, so we'll probably go with him. I'm looking through his paperwork. There's info about measurements and code for egress and a Rockwell brochure that shows a polycarbonate cover. But he also showed me a picture of another cover that was not Rockwell. I'm not sure what it was. Is polycarbonate the best for letting light through? Are there different kinds of polycarbonate? Are there better brands? Thanks.

Thanks. That sounds like a good plan!

I have a related question. How does she get fresh air in the basement if there is a cover on the window well?

You use the "grate" style if you don't want to remove the plastic one. Your well is required to have a drain, so just have to clean up the leaves.