Do you mean 'solar passive' or full 'passivhaus'? I'm not aware of windows being central being a feature of solar passive, though size in relation to room size is relevant, and orientation of course. I'm confused by the differences ranging from a millimetre or two to inches and a foot? I think more to the point, if what's built is not according to the plan is it within acceptable variation or is there going to be a problem with not being built as approved?

I’m assuming that you mean millimeters on the plan translating to centimetres once constructed. You’ve signed off on the plans so any solution will be by negotiation with the builder. Moving an interior wall is fairly low fuss but moving windows is a major job once the windows are fitted. See what you can negotiate with your builder.

yes - on the plan it is off by millimeters - so hardly noticeable until they were installed - the actual window is not installed but the opening is - these walls were built in their shop with the windows cut out - yes it is a passivehaus. Our builder admits he never noticed either - my concern it not whose fault it is, just if it is possible to change it now - the walls are 10 to 12 inches thick and all come insulated etc.

Anything can be fixed if your throw enough money at it. In this case it looks like you’d need all new walls manufactured again to move the window placement, otherwise you’ll lose the “sealed” effect of the walls when you cut into them. But the best person to ask is the manufacturer/supplier.

Oh well we definitely can't replace the whole wall - that is a very big deal - the roof is on already. It is just so disappointing - they are not off centre enough to make it look like it was meant to be - in a 10' wide room I have approximately 4' on one side to the edge of the window and 6' on the other side to the edge of the window. I know the wall can be moved but it will make my bedroom down to 9' and we will have an extra foot in an already wide hallway - the hallway also has a window in the middle ( supposed to be middle) which is off by about 8" - so I can fix one but not both and by fixing one, the other room is not a functional.

Stick with functionality and leave the room size as is. You may be able to visually balance out the lop sided windows with window coverings. But do ask your builder if anything can be done with the windows before you accept the situation.

Thank you - at this point he was willing to move the walls but I had already decided that wouldn't work - in the large hallway we have windows at both ends, both off centre. I know I can balance those by putting something tall in the corner that is wider and then centering furnishings etc. (the hallway is 8' wide - reading room at one end, office desk at the other) My concern is the bedroom for the two granddaughters and having two beds there - it is definitely going to look odd - the nightstand between the two will not centre under the window - I know there are more important issues in the world but it is so disappointing - this is the designers fault, not paying attention to detail when drawing and getting them exactly in the middle and then the rest of us not seeing that millimeter or two on a piece of paper (obvious now that we know)

That's very disappointing if you told the designer one bedroom was for two beds with a bedside table in the middle, so a symmetrical layout, and they overlooked that criteria.

Well - I did not tell them that I was having two beds with a table in the middle, but as I said, the window was supposed to be in the middle, the designer just didn't get that right - in the plans it is hard to tell it is off but once it was built and the walls were in place, it is very obvious - an inch or two I could live with but one foot in one room and 8 inches in the other is too much. Not enough to look like it was meant to be that way unfortunately.