A modular home factory in Wilder, VT has opened to build zero-net energy mobile home replacement units. While there have been other efforts to replace mobile homes outside Vermont, they have done so with newer manufactured housing units that suffer from poor indoor air quality, high energy costs, and durability issues. This session will provide an overview of the issues with manufactured and mobile homes including financing and depreciation, attributes of the zero-net energy replacement modular home, the design and build process, and the comprehensive whole-house monitoring system. Detailed monitored energy and environmental data will be shared from two years of occupancy. The session will also discuss design challenges/constraints associated with cost, prefabrication, and transportation of a Modular/mobile home. We will present a comparative look at cost and energy with other related housing initiatives, as well as show the cost to benefit analysis of what it would take to bring the project to the Passive House level.