Thanks for the smart points about rain, klem. And I agree -- there are just so many options, and people are so opinionated about those options, that it's hard to know what to do. My biggest concern remains the weather and how that will affect things, but I know that's a local issue. Maybe I should walk around the neighborhood and survey some people with porches about the sun and the temp, etc. Without adding any new information, my wife and I are divided on what to do -- she thinks just screening it is fine, but I think it would be really nice to have glass for the late fall / winter. If we had to decide today, I think we would either do simple / cheap modern storm windows (which could be opened to the screen on the bottom half during the summer) or do something a bit more adventurous. What I'm thinking on the adventurous front is to screen it in, but do it in a way where there's space to add the old-style wooden storm windows later -- just simple single-pane units that slide into the windo frames and attach with this: http://www.houseofantiquehardware.com/screen-hooks-storm-sash-window-hanger?sc=12&category=91 . The main thing would be attaching the screen on the inside of the frames, or at least creating an outside sill deep enough for the storm windows to nestle within it and still be flush on the outside. Then we could remove the storm windows and store them in the garage during the summer (though that wouldn't help with rainstorms you mention). Does that make any sense? If we did that, we could see how we like the screen in the spring and summer, but add the glass later in an affordable and removable fashion. I haven't seen many people try this, but I think we could build the storm frames and get the glass cut by a local shop. Basically we would recreate something like this company's product: http://chicagogreenwindows.com/storm-window-primer/

It would be great if you could attach the picture of your season room, so we could clear suggestion for your window options. For a three reason room, it should be allowed for much light to come in and use slimmer profiles to show its modern style. I would suggest you to use thermal break aluminum tilt turn windows and doors for the room. 4 track windows seems to offer the maximum ventilation however in real situation, probably you don't actually use quite often or if you do, you could consider making them into a big glass doors. That's my suggestion without knowing the drawing, and you are free to ask for help by reaching us at our site of ChinaWDMA windows.

Those are called mullions or muntins. They are repairable, if you have the time to do it yourself or the money to hire someone else to do it. Depending on the age of the room, it may be cheaper to replace the windows and frames, but they look so lovely on the inside, it's a shame not to repair them. Do some internet research on wood repair, or buy some books on how to do it. There is a famous book called "Working Windows: A Guide To The Repair And Restoration Of Wood Windows" that explains how to repair old windows. There is a lot of good info on the Old House forum here.

Have had at least three broods every season and don’t remove the nest until cleaning in the fall.