Over 1 billion people globally currently lack adequate housing. In Mexico alone 49 million people lack affordable, permanent housing. The housing development market generally ignores the poor and is rife with exploitive credit intermediaries. For over 25 years Francesco Piazzesi, the founder of the social enterprise Échale a tu Casa, has been working in Mexico to improve housing conditions for this excluded population, and he and his team have developed a truly comprehensive, elegantly integrated model that combines community empowerment, local technical capacity building, a novel affordable financing system, and exemplary cutting-edge but culturally appropriate “green” building techniques, including breakthrough innovations to adobe block construction, rainwater harvesting systems, bio-digesters to treat human waste, grey water filtration, clean-burning cook-stoves, solar water heaters, and sometimes photovoltaic panels. Over the last 6 years Échale has provided 30,000 new or radically improved homes at an average cost of $10,000 and helped provide an additional 150,000 home improvements. It is now on track to meet its goal of producing 10,000 homes a year across 22 of 32 Mexican states via community-based social franchises, and extending the model through strategic partners to South and Central America. Échale offers one of the most promising models to provide healthy, “green” housing to the world’s most disenfranchised citizens.