LUMENHAUS is completely powered by the sun. A powerful array of Photovoltaic (PV) panels provides carbon-neutral energy to the house. The PVs, arranged in a single array that covers the roof, are built into the house during construction. The panels are bifacial, meaning they use both sides to increase energy output by up to 15 percent. Using an electric actuator, the entire PV array can be tilted to the optimal angle for each season (from zero degrees to a 17-degree angle in summer and to a 35-degree angle in winter). Having the array at the correct angle allows for maximum solar energy collection. There will also be PV wafers located within the skylight in the bathroom.