I don't have weatherstripping on the door panels but since aluminum is such a good conductor I covered my doors with the good bubble Insulation from Charlie's. Their is not room on the inside door needs to open so I put it on the outside. I live in Northern Indiana and it gets cold here so I have mine well insulated.

marti8a- We have 2 sets of aluminum clad, low e, argon filled sliders and a set of the same outward opening french doors, all by Eagle (now owned by Andersen, but independent when we purchased them 8 years ago). They all operate easily, close securely and have no air infiltration, we are in NNY and have wind, cold and snow and have never had a problem. While I like the look of french doors better, we chose sliders in two our of three locations because we wanted screens on the doors, we don't have or want A/C, so screens are on the doors are a must for us. The one french door we have will someday open onto a small sunroom/conservatory (hopefully), that's why we chose a set of french doors in that area. Eagle, as well as the other well known manufacturers, have lots of options on the interior; primed, painted, stained, different wood species, hardware options, etc. We rented a house with vinyl sliders when we were building and I would not recommend them at all, they didn't work well, ice built up in the channels and the cold air poured in seemingly from the entire opening. I strongly prefer the wood interior and aluminum clad exterior, but overall I would get the best ones you can afford, good doors and windows pay for themselves in the form of lower energy costs. Good luck- sandyponder

366 glass is LowE3, and is the most efficient in blocking unwanted UV but letting in light. There are various grades of glass that anyone you deal with will be able to explain and apply to your needs. In vinyl products, I have seen the most service issues in patio doors. At one time I thought they were wonderful, but over the years I have seen so many vinyl doors that haven't lasted very long at all. You seem interested in a wood interior, though. My opinion is that vinyl and wood don't go together well - different expansion and contraction rates. But look around and see what you like, and get a good warranty. When you do a project like this on your home, you want to do it one time. You want to enjoy it and love it. You want it to last. While you don't need to get a gold plated patio door, you need to understand that if you shop price to just get by, you will end up with an inferior product and workmanship, and ultimately be unsatisfied. I encourage you to get a quality product and have it installed by someone that will do an excellent professional job. I encourage you to not buy from a big box store. They are notorious for rushed hack installations and mid-grade products. You don't want to spend a significant amount of money and end up wishing you had never done the project at all. Quality product, and an installation company that is committed to quality and 100% customer satisfaction, with warranty guarantees and a good service record.

consider your floor plan, and where you want the opening(s) to be located. if you are veering around a central grouping of furniture, having an option to go right or left is good. if the furniture is more to either side, the center door works. i like 3 sets of french doors, they are far easier to open and close than giant sliding panels. but that swing has to be arranged around.