I actually had a glass house for my pair. Here’s the thing though, rabbits don’t do well in hot temperatures. They love to lounge in a bit of sun, but once it gets past a certain temperature they’re going to struggle and risk heat stroke.

I designed the glass house to have a warren with clay pipes, creating an area which was definitely cooler that they could go relax in and that was a good temperature for them, but we still had to be careful. We also had sheltered overhangs that they could get out of direct sunlight but still be out and about.

Where i am it general doesn’t get eccesivley warm, but sunrooms/glasshouses get HOT.
We also used a cover for the house to keep the sun off so it wouldn’t over-heat.
Id think about installing windows and doors that will allow for a good current of air to go through-without riski g escapees, and blinds, to keep the sun out at times, or put just on sections to try create a temperature gradient. (seems counter intuitive in a sun room)

Get a thermometer as well, and keep an eye on it. Rabbits can adjust to heat, but not so much to huge temperature changes. So if the sun room is roasting during the day, but the temperature plummets dramatically over night it makes it unsuitable – my rabbits slept in the main house at night because glass houses get crazy cold at night compared to day time temperatures.
Hope this helps a bit!

Four seasons sunrooms usually have central air/AC/heating, so they’d be totally fine in there So if you weren’t planning on that, I would definitely make sure you can have central air or at least AC in it. But it’s not like a porch, so it would obviously be insulated and protected. I think the other thing would be carpeting. I know it sounds silly to put it in a sunroom, but your buns will thank you.