The Suntracker uses GPS and mirrors track the sun throughout the day, and bounce it directly down on to a diffuser. So as long as the sun is up, the skylight is capturing all available sunlight and beaming it into the house in a way that maximizes light. Most Ciralight customers are industrial or retail companies, but the company also offers home installation. The price is about $1,100 to adapt an existing commercial unit for a residence, but they're working on a 2'x2' model for homes (price to be announced).