From wiki article on zero-carbon housing
“An example of zero-carbon housing is Earthship Biotecture. Developed by Mike Reynolds, the Earthship is an environmentally friendly 100% sustainable type of home that can be built anywhere and in fact have been constructed all over the world. They are constructed with materials that would normally be discarded to take up space in a landfill including old tires, bottles, and cans.
Reynolds has three requirements for Earthships. One, a sustainable architecture using natural (non-manmade) materials as well as recycled materials is utilized. Second, dependency on natural energy sources only (”Off-the-grid”) and third, be financially feasible and a do-it-yourself concept so an average person could build their own Earthship.”
Not that the first two parameters are workable for anything but a tiny fraction of homes but that third one ensures that zero zero-carbon houses would or ever could be built.
Most tract homes nowadays are built like trash anyways so why not use trash to build them!