The “Houseboats to Energy Efficient Residences” studio explored how to rescue Kentucky’s flagging houseboat industry and create an affordable, energy- efficient alternative to shoddy, energy-inefficient trailer homes. The goal: a $100,000 house that runs on $1 a day. My project - the studio’s only two-floor plan - uses an 18-inch grid, concrete insulated forms, a green roof and passive solar and geothermal strategies. Key is a factory built core containing all utilities, bathrooms, kitchen and stairs. The core is made with recycled plastic bottles, liquid-filled for thermal mass and a sky-light source.