The four single-family homes built on Woodside Avenue are part of a ten-home urban infill project in Ferndale, Michigan, a northwest suburb of Detroit. In order to meet the goal of creating affordable housing, the homes are built with an optimized enclosure and mechanical system. Improving the enclosure by increasing airtightness, providing high performance windows and fully insulating walls, roof and foundation allow the home’s mechanical system to be downsized. A smaller mechanical system costs less than a conventionally oversized system, leaving money to cover the costs associated with the above enclosure improvements. The efficient 1 ½ story floor plan is advanced framed with 2x6 wood stud walls at 24" on center, saving material costs while both increasing the wall’s thermal performance and decreasing thermal bridging. These homes operate using 30% less energy than a home built to code in 2006.