When it comes to patio door materials, aluminium is easily the most sustainable option. This is because aluminium can be recycled almost endlessly, so no waste is created when you decide you need new doors - your aluminum frames can be turned into cans, window frames or more doors.
Of course, a lot of other factors will effect the overall sustainability of your aluminium patio doors - take a look at our post on eco-friendly patio doors for more tips on picking an environmentally friendly solution for your home.