Airtight construction saves energy and improves the durability of buildings. While an energy efficient home can never be “too tight”, since it is so airtight, it is necessary to provide a clean, healthy indoor environment. This involves three steps: reducing or eliminating indoor pollution sources, installing automatic, controlled ventilation, and providing air filtration. A good way to address all three steps is to participate in the US Environmental Protection Agency’s Indoor airPLUS program. Following good design and construction practices, a zero energy home is much healthier than any conventional home.