Many new materials and techniques have been designed to cut energy losses in residential construction. They help the builder and architect in almost every aspect of energy-efficient house construction from the foundation on up. One area that product designers have overlooked, though, is the chimney. At this time, there are few techniques and materials specifically designed to block heat loss where a chimney breaks through the building shell. From my perspective as a fireplaceproduct designer, I see no easy solutions short of new-product development and, possibly, code changes. On the one hand, we must remove heat from around the chimney to maintain safe temperatures on adjacent combustible materials. On the other, we want to reduce heat loss from the living space. Each