We came across this article on www.greenbuildingadvisor.com that discusses long term air quality issues resulting from a poorly designed and installed exterior envelope in a Green building in Belgium.  In reality, all of the individual components used in creating the high efficiency home design, worked in theory, but in practice, and under poor supervision these products did not work well together.   The most important thing we have learned over the years has been how critical proper ventilation is to a healthy home.  Indoor air must move, and needs to move enough to evacuate built-up moisture in the home.  Properly insulating a Custom Home, or a renovation  is always tricky, but we have found that proven materials, installed properly always work. 

Here is the full article from GreenBuildingAdvisor.com: http://www.greenbuildingadvisor.com/blogs/dept/musings/belgian-passivhaus-rendered-uninhabitable-bad-indoor-air