The Fern has been designed as Sydney’s urban oasis and is Australia’s first Passive House apartments. Energy efficiency, filtered air free of allergens and pollutants, quiet and delightfully detailed interiors are all achieved without the ongoing use of fossil fuels. Set on a challenging, compact city site, the passive solar design was made difficult by the necessity for fire rated walls on the north and south boundaries making the only opportunity for locating glazing and typical ventilation on the problematic eastern and western boundaries. The Fern achieves passive house principles of stringent air tightness, continuous unbroken insulation, high performance glazing, structural thermal breaks, and heat recovery ventilation, all while nestled into Sydney’s vibrant urban landscape.