Yes, they certainly have to meet requirements for air exchange. And if you define “airtightness” as that, then yes, the ones that met that definition met that definition. What they are not is the common definition of airtightness, as in a sealed glass jar, steel can, scuba tank, or submarine, which if you look at the comments here was what was confusing a lot of people. I don’t think anyone was contending that there aren’t tests that these houses have to pass, just that the word airtightness, as understood by laypeople, isn’t an accurate term to describe these homes.