Graham Irwin, AIA, NCARB, is the principal of Essential Habitat Architecture, a Northern California design firm focused on healthy, high performance, sustainable buildings that meet or exceed Passive House/Building standards. He has a degree in physics, with additional studies in engineering and architecture, and an extensive background in software development. Since 2008, his firm has worked on numerous single-family, multi-family and commercial Passive House projects throughout California and the US, including the first certified Passive House in California, the first certified Passive House retrofit in the US, and the first certified multi-family Passive House in the US. Graham is a licensed architect and licensed general contractor in the state of California.