Wind turbines stand tall and mesmerize with their motion. Solar cells bask in the sparkling sun. Meanwhile, hidden down in the dark dirty underworld, a compelling technology sits quietly and gets no respect. Once installed it largely goes unseen and, it seems, it's equally invisible in the world of clean technology press, venture funding and government R&D funding. Yet this technology provides some of the most intriguing economic returns available for reducing a building's net energy consumption and I would welcome the right opportunity to fund an exciting business in this category.