I would have the size of the sunroom to relate to rest of your house. You don't want the sunroom to be too large in relation to the overall house. Someone with an eye for design could assist you there. We had our sunroom added on 18 years ago. At the time I researched ways to make it energy-efficient. One recommendation was to have tile floors as the tiles absorb heat during the day and release it at night. There are also other recommendations such as the type of windows (we used Anderson low-e) and the amount of roof overhang. Another factor to consider is the orientation to the pattern of the sunlight during the day. We have a Cape Cod style house with the sunroom going off perpendicular to the house at the rear. We have a great southern exposure and I am able to grow geraniums there all year round. Another area to consider is the backup heating for your sunroom if you live in an area where you would need that. The remainder of our house is oil-heated but we have an electric baseboard heater in our sunroom and it really runs up the electric bill. (We keep the sunroom closed off except when we are using it because of the cat getting into my plants.) There are books out there that would address all these topics. Look at Lowe's or Home Depot.

Ugh still dealing with this and asking for help again. I was totally set on the bluestone sunroom floor until the quote came back at almost $5,000. The room is only 190 sf and a perfect rectangle. No cuts and little material waste. It's just way out of budget for what I was planning to spend on that floor. I was planning around $2,000. So I'm back to finding another solution and am stronglyg luxury vinyl planks in a whitewashed wood. I think it will give that back porch feel I was originally going for. The problem is I can't find one I like. They are all either too rustic, too grey, etc etc. I found a laminate that is a pretty good match for what I'm looking for but I don't think laminate will hold up. So I'm looking for a good quality LV in the same vein as the pic below . Am also open to other flooring suggestions or ideas in how to make my bluestone dreams a reality.

Our floors were open to ground also. We had foam sprayed in from the underside. In some places, where it was a tall enough crawl, we had pink stuff, foil covered foam installed under the floor joists, taped and touch in foamed along edges. We did get occasional leakage between boards, once peeled out, ya don't even notice.

Sofa and chairs = neat. Worth thinking about how you are likely to use the space. When I have used a sun room it was mostly morning coffee and a daytime chat or relax. If this is the case, side tables and a large ottoman is really useful. Glass tables do not work well visually with an oriental rug unless you are making it work with an eclectic look all around.