I'm in Urbana at the Passive House Consultant Training course, and am quickly realizing that my early attempts at PHPP calculations were just scratching the surface. Also a case of knowing "just enough to be dangerous." To make the annual heat requirement, I created huge southern glass areas, which, I found out, create huge daily temperature swings, will require lots of summer cooling, and (of course) are expensive. It's Tuesday, day 2 of 9, so there's much to learn...not to mention the years of learning to follow.
I will continue on the prototype development once I've completed the course...