What I object to is the r value of Tyvek.
The r value is apparently 2. That is very low. An r value is a number based on the ratio of heat transmitted through any object. The r value compares the heat on one side to the heat on the other side. A high number is what architects want to keep heat inside the house in the winter and keep it outside in the summer.
The problem is that Tyvek does something extremely important for comfort that is not relevant to its r value.
I was involved in the earliest solar no-purchased-energy homes. In visiting one such home high in the mountains when it was surrounded by 7 feet of snow, I was amazed at how warm I was inside the house.
The reason I was warm and comfortable was the absence of drafts. The architect explained that people feel cold even in a warm room if there are drafts on their feet.
Tyvek is a metallic plastic wrap that completely covers the house. The consequence is that it blocks all air leaks and undesirable airflow.
As a consequence Tyvek does more to make a house comfortable. It truly increases the emotional r value far more than an r value of 15 or 20.
I hope people concerned about r values are sensitive to this reality.