Is it just me or is this a very confusing and surprising document?
It's confusing in part because it's the combination of a German standard and some PHI proscriptions that differ. It's very surprising to me that for something so fundamental and so important as the floor area measurement, the PHI hasn't produced its own clear and unambiguous specification.
This version has been tidied up from the previous draft that we saw and at least the colours match now, though not providing numbers for the figures makes it a little more difficult to discuss them and the lack of page numbers makes it even worse. For instance, on the second page there are two figures that appear to be identical. Is that a mistake or are they supposed to be the same and if so why repat the figure?
Most of my confusion stems from trying to interpret the actual meaning. I suspect some of it may make sense in whatever context the German standard is normally used but not when it's used in conjunction with PHPP.
On the third page, for example, why would the energy demand of the whole floor of a building depend on whether one room is 'inhabited'?
And why is the basement corridor, which is closed off by doors from all the rooms not excluded from the TFA as it says it should be on the second page?
On the fourth page, it says "living area is thermally separated by a door between corridor and living room", but what does that mean? Normally an internal door in a house would not be thermally insulated and in a passivhaus it might well have a gap underneath to ensure the MVHR works properly. Are they just saying that there's a door and adding the bit about thermal separation to confuse the reader, or are they saying that the requirement is for an insulated door and if so, what U-value is required?
Similarly, looking back at the left hand figure on the first page, where is the thermal envelope? Is the triple glazing in the main building wall, with a lean to single-glazed greenhouse, or is it perhaps triple glazed all round the outside with a decorative divider? And are the two cases treated the same? How are solar gains allocated? Is the greenhouse assumed to be maintained at 20 C?
Back on the second and fourth page, it says that [full width] steps are included in the TFA, but a [part width] flat opening is not. Presumably a full width flat opening is included but exactly how big a stub wall is needed before it is excluded?
Why is the bifold door on the fourth page treated differently? Is it a step and if so what difference does that make?