Buyers are demanding homes that won’t make them sick. This means that builders, who are pushing to make their homes energy efficient and airtight, must be extremely careful about the products and materials they use. It’s the Catch 22 of energy-efficient construction: Well-sealed buildings can trap in toxic chemicals, mold, pollen, and other irritants. It takes a range of building science-based strategies—from proper ventilation and moisture control to radon mitigation and conscientious construction practices–to make sure a home is healthy. Read about some of these strategies here.