The idea and work is inspiring, though they made a number of significant mistakes that reduced the livability of the house. Their cold climate and construction details caused persistent condensation and mold issues, and the design and construction of their
rocket mass heater was so inadequate that it never worked and they tore it out.
So look at that
project as a lot of good demonstration of things to do and not to do. Study the subjects involved along with their experiences to learn how to distinguish the two.