We have a walk out ground level patio that we want to enclose with a patio door plus windows to maximize the view. The patio already has a ceiling (the upstairs porch) and sides, so we are basically just adding one wall, which will be the sliding door/windows.

The new wall is 21 feet wide by 7 feet high. The room will not get additional heating and cooling, instead we will rely on the existing room HVAC. The entry to the patio from that room is 2 patio doors, each 8 feet wide (i.e. each has one sliding panel that is about 4 feet wide). The plan would be to keep these existing doors open to allow for heat and cooling into the newly enclosed space.

We live in Northern Virginia. Temperatures here are hot and humid in the summer (90's) with relatively mild winters. We will use the room mostly as a gym in the daytime hours, so cooling is more important, on balance, than heating. The room faces due west, and since it is sunny 300+ days a year, afternoon sun is an issue. Since the current room has the patio overhang of over 10 feet, this is not an issue now, but the new room will have virtually no overhang and so will receive a lot of sun.

We live kind of far away from major cities so it is not easy to get to many dealers -- even the closest Marvin dealer is over an hour away. We may be limited to Home Depot/Anderson (the 400 line), although of course I'll try to get something else if this is a terrible choice. Given the small size of the job, I can't get a mfg rep here (I tried!). So many of the brands that get good reviews here are probably not an option. Just as a note, we have over 200 all wood Anderson windows on the house (1973) and they have been fine except for the casements -- the opening mechanism is so flimsy (a thin piece of aluminum on only the bottom of 6 foot tall windows) that we don't dare open them, ever. Otherwise no issues with condensation, rot, etc. More recently we installed Anderson skylights, and while the windows themselves are fine, the motor mechanism and design leaves much to be desired, so all in all I'm kind of mixed on Anderson.

Our current thinking is either 2 side by side, 8 foot wide patio sliders (like the current entry to the space) or one 8 foot wide slider flanked by ~5 foot wide stationary casements.

Questions:

1. Wood vs vinyl vs aluminum vs ? Newbie here, I've never bought windows. Strong pros and cons?

2. Screens. Are the retractable screens okay for occasional use? Do they hold up?

3. Glass: I looked at the Anderson options: Would the Low E4 "SmartSun" option be appropriate? The "Sun" option appears to have a dark tint. I can't quite figure out the Martin equivalents to these.

4. Anything I need to have in mind when ordering? Special options, etc?

Any and all comments/criticisms/recommendations appreciated!