Hi Mizfixit! Thanks for your interest in our work. This house was a design-build project by Palo Santo Designs and although atypical in its very small size (under 1000sf); we applied all the same principles of sustainable design and construction to the house that we would to any home. A super insulated thermal envelope, R-30 walls, R-50 roofs, ENERGY STAR rated windows and doors, ultra high efficiency heating with in floor radiant, LED lighting, and indoor air quality features like non-toxic finishes and Energy Recovery Ventilation.