I spent a long time thinking (and boring Steve) about windows. It still surprises me – given how much windows cost and how significant they are in terms of the whole look of the building – that you don’t really get to see the details of the windows before they physically arrive on site. By that time of course there isn’t much you can do about it. You’re provided with lots of functional information (that’s fairly unintelligible to a non-expert like me) and there are usually some fairly basic photographs of window components (although in our case, what was on the manufacturer’s website didn’t match with what we were being quoted for, which wasn’t helpful), but we ultimately just had to trust that the window frames and handles would all look and work OK. And also that we’d like how the windows and doors opened and closed. Note to window manufacturers: definitely an opportunity to use digital technology more effectively so that you can actually show your customers what they are getting.
Passivhaus Homes (PHH – who supplied our kit) sourced the windows for us, through Austrian window supplier Katzbeck. PHH are increasingly using UK based Green Building Store for windows, but unfortunately they don’t currently supply Scotland, so we had to import. That said, the windows are extremely good, aesthetically, functionally and in terms of their extremely high thermal performance (which we need for our house design and location to achieve the Passivhaus standard). Whilst a lot of mid-range manufacturers have similar high performance glazing, apparently the real difference is in the frames where most of the heat loss and thermal bridging occurs.
One thing that I’d not really thought about before was whether windows should open inwards or outwards. In the UK (aside from sash style) traditionally windows have tended to open outwards. Newer windows often provide a tilt feature, meaning that they increasingly open inwards, which also allows for easier cleaning from the outside (but less stuff being able to be put on window ledges!). For Passivhaus builds there are also thermal benefits for inward opening, as more of the frame can be insulated from the outside. Our wood fibre overlaps each frame by 40mm all the way round, with specific tape then used to tape the edge of the window to the membrane/wood fibre, further eliminating any air gaps.
Unfortunately I wasn’t on site when the windows were put in – the one major step in the build that I missed. They were apparently extremely heavy! Now they are in, I can confirm I was fine to trust that they would be OK. Phew. Both the windows and in particular the doors have a very satisfying solidity to them. The view through them all is pretty good too…
Sitting room windows:
and through the round window… 
front door