The San Francisco Federal Building is an 18-story office building designed by architect Thom Mayne to be naturally ventilated using thermal mass and passive shading. It houses several federal agencies and was the first naturally ventilated high-rise office building on the West Coast since the adoption of air conditioning. Key green features include large amounts of concrete to facilitate natural ventilation and cooling, stainless steel sunshades, and operable windows controlled by sensors to allow natural ventilation. The building is expected to consume about half the power of a standard office tower and received LEED Silver certification.