It’s been 40 years since the 1973 Oil Crisis thrust the United States to the forefront of passive solar heating. But have technologically advanced building systems rendered passive strategies obsolete?
LEED v4 for Homes contains a three-point credit for optimizing a building’s orientation for passive solar heating. Details of the credit are specific to managing the amount, shading and orientation of south-facing glass. These are sound design strategies, but their contributions toward an optimized passive solar heating system are limited. Homes that implement these strategies still run the very real risk of overheating during a sunny winter day. Diurnal temperature swings may still siphon heat from the south-facing glazing.
The point here is not to criticize LEED. The absence of a robust passive solar heating component to the LEED for Homes rating system is symptomatic of a broader oversight of passive solar heating by the high-performance design and construction community. Green building has become so sophisticated that we may ponder whether passive solar heating is still relevant. Yes, technological advances abound, however the physics of passive solar design have never changed. The lessons remain, and the vast body of work of decades past holds much value for those who care to retrieve it.