Triple sounds like it could be a good fit based on your comments about occasional cold weather.

One thing to keep in mind is that there could be a substantial performance differences between different triple pane windows, some are great and some are not. There are even triple pane windows that don't perform as well as the best duals, so it's important to know what you are getting.

Do you have a particular window in mind?

Quality of the door itself will have almost as much effect as the glass, a crappy door with the worlds best glass package will still be a crappy door. What brand and type door are you looking at?

+1 to both previous comments. I would be looking for a door that has good air tightness numbers and triple pane.

What region/climate is the home in?

I am looking at the Okna 8800 sliding door. Here are the 2 glass options I am looking at. I am in growing zone 6b in southern PA

Go with the triple, good choice

" I am looking at the Okna 8800 sliding door. "

Good choice and I agree completely with the above, triple for sure.

+1. Great door, triple is the right choice