Inspired by the Existenzminimum movement of the early 20th century, the feasibility of historic efficient housing concepts is studied. The canvas for this is the renovation design of a post-65 housing complex in Amsterdam. Three concepts reinterpreted into a modern context and applied in the design. The first is a sharing concept with smaller individual homes and shared amenities and functions. The second is a flexible plan concept in which the home itself is made as efficient as possible. The final implemented concept is a institutionalized squatting concept with lowest rent possible. The feasibility is assessed through judging the design in 18 categories before and after the renovation.