The Courtyard House Plug-IN was first developed as part of Dashilar District’s Urban Regeneration Program, an highly populated historic area in Beijing dotted with traditional courtyards, which, old and dilapidated, are often vacated for newer housing in the suburbs. The prefabricated panels are made of a composite incorporating structure, insulation, wiring, plumbing, windows, doors, interior and exterior finishes into one molded part. The entire, mass-produced structure can be assembled by a few people in one day, and requires no skill or special training. Courtyard n. 72 is the first prototype, functioning as a live/work space for guest researchers, with a 40m2 office space and a 20m2 guest room with bathroom. The system also presents an alternative approach to preservation. It extends the life of houses by upgrading their relevant functions and keeping the original building untouched, suggesting that an ideal way to preserve buildings is to have people care about and use them.