I've read a lot about the benefits of passive house design over the past few years on ebuild and other forums, but not much on any negatives.   My biggest concerns with passive house design have always been around air quality and internal temperature. I really struggle in stuffy environments. I even open windows in winter.   I was researching the above and stumbled across this.    http://repository.tudelft.nl/islandora/object/uuid:88fd72b2-f7ab-45ea-a403-ce367801cf3