This story was originally published in Dwell’s February 2012 issue.

The world owes Germany a Danke schön for its green standards, but the JustK house does zero-energy with unusual style. Amunt incorporated a geothermal heat exchanger and triple-glazed windows into the strict planning regulations, which dictated the pitched roof and narrow structure (the asymmetric profile accommodates a neighbor who asked that her view of nearby Hohentübingen castle be left intact). Built for Dominik Bless-Martenson, Katrin Martenson, and their four children, JustK (the name comes from its location on the Justinus-Kerner-Strasse) can be divided into two separate units, giving options as the family grows up and leaves the nest.