A complete renovation and second-storey addition transformed this small East York bungalow into a modern and more spacious family home with abundant natural light and greater energy efficiency. Environmental sustainability was a key priority for the homeowner. The renovated structure incorporates passive solar design, stack effect cooling, cool roof technology, high levels of insulation, great daylighting in all spaces, a green roof, rain garden, rain harvesting, and local, reclaimed and recycled materials. While the renovation nearly tripled the size of the original home, the homeowner’s heating bill was cut in half. The new design also maximizes the functionality of every square foot of the house; even the dead space above the principal staircase was utilized to create a secret playroom that is accessed from a ‘magical’ door in the children’s bedroom closet.