I couldn't tick one or the other of the boxes – I think the choice has to be made contingent on so many variables. In fact we have painted timber, double-glazed bifolds (with a fabulous retractable pleated fly-screen) at the end of the dining room leading out onto a terrace and a painted timber, double-glazed slider (with a timber-framed sliding fly-screen) on the other side of the kitchen (but on the same axis) opening onto a raised timber deck. Each works really well in terms of function and aesthetics but they would not be interchangeable as the different locations determined which was more suitable – but they have been made by the same highly skilled window craftsman and have given us nothing but pleasure. And on a hot, steamy evening with both open we have the most wonderful cross ventilation.

A sliding door is just a big window, and if correctly built in (check if the glass is the correct sized for the door if a bit old) with the correct sized lintels this should not be a big problem as the loads would be transferred to the sides, allowing the door to slide easily. Silicon spray (being a Yachtie were we use this stuff everywhere), we now use silicone spray on all our windows in our 1930 home and the windows glide across with one finger before they used to tilt when trying to open them. I would place the door head up to line up with the others and one thing you might consider is placing a window seat, (rebate the bottom channels into the window seat) and have the window seat in and out, place a cushion over the entire seat, should be fantastic and if the deck is built, than no balustrade is required. If it is a stacker slider, i would do the seat for the entire length. So instead of looking a bit funny they will think it was supposed to be like that. We should all think outside the square more often. RAM

While both are great options we agree with Tribbletrouble44152k7 Trek - definitely depends on your space. We personally like swing or pivot doors - easier to clean, space efficient and easy to assemble if you are doing it DIY. Alternatively you could use a glass screen and do away with the door all together if that's possible? An example is below of our DIY shower screens, which you can also pick up with door kits: Hope this helps! Let us know what you decide.

What performance is more applicable for your climate? Double glazing will perform significantly better than single glazed whatever in regards to heat loss. You can't beat the air gap factor if you're trying to keep avoid heat loss. Yes there are "Low E" single glazed products such as viridian Comfort Plus which depending upon which side of the glass the absorption coating is placed it will perform in different ways, but bear in mind that since it also will reduce heat gain in winter it can actually work against passive solar building performance if not properly applied. In other words, it's not a "cheap" replacement for double glazing. In Victoria, we generally spec standard double glazing and use external controls such as blinds to mitigate heat gain issues in summer. Thermal Performance Specialists such as an Energy Raters understand the technical nitty gritty around this issue the best, and always good to seek their expert advice when applicable.