Energy efficiency meets clean design at Villa Kogelhof by Paul de Ruiter Architects. Located on a protected habitat, the house is split into two spaces, one underground, and one suspended above it. The subterranean level houses the entrance, garage, storage, and a workspace overlooking the pond. Upstairs, you’ll find the living quarters, including the bedrooms, kitchen, bathroom, and patio, set on an open floor plan with a glass facade. As far as efficiency goes, there’s an air circulation system, a central heating system, solar panels on the roof, a biomass stove for heating water, and a windmill. And don’t worry about the wide-open surroundings: over 70,000 trees have been planted that will provide plenty of privacy in the years to come.