First, the engineering was done by a committee of accredited PassivHaus designers (not me, I came in later) and if you read the literature, they are all different and all need some form of heat at some time. I'm not out of a job because I do much more than heating. The ERV is integral in this process, there is still a heat load and a cooling load and if you read the requirements, the load must be less than 15w/m2 which this house is.
No house is perfect and this one has, amongst other issues, a couple of evergreens that shade things a bit (for example). It is bigger than the average house of its type so the issues are compounded somewhat. It will house 7-8 people so it will have a higher than average DHW load and will have more load swings than a house with 2-3 people. The heat/cooling loads were done by 3 different companies, including WattsRadiant and they all came within 15% of each other (which is unusual).
No one is flying blind here, but for every problem there is 10 solutions and you have to narrow it down. As I mentioned before, even heat is important and more difficult to achieve with a group of ductless HPs so a compromise was made.
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