The Thermal Envelope House

By Richard Freudenberger
Published on March 1, 1979
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A wintry day provides the perfect setting—and the perfect test—for the thermal envelope house. Sunlight reflected off snow can furnish up to 30% of the home's heating needs
A wintry day provides the perfect setting—and the perfect test—for the thermal envelope house. Sunlight reflected off snow can furnish up to 30% of the home's heating needs
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Young Taro Smith plays on a tire swing, one of the fringe benefits of the greenhouse.
Young Taro Smith plays on a tire swing, one of the fringe benefits of the greenhouse.
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Tom Smith looks over the second floor balcony. The greenhouse is below him.
Tom Smith looks over the second floor balcony. The greenhouse is below him.
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The master bedroom offers a choice of views.
The master bedroom offers a choice of views.
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The living room stays warm without help from the wood stove most of the time.
The living room stays warm without help from the wood stove most of the time.
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Diagrams shows a cross-section of the envelope house the convection pattern through its inner and outer shells.
Diagrams shows a cross-section of the envelope house the convection pattern through its inner and outer shells.

An ancient Japanese proverb states that “the simplest solution is the best.” If that’s the case (and we think it is!), then this attractive house–nestled high in California’s Sierra Nevada mountains–is one of the better solar-heated homes around, since its design allows it to store heat during the sunlight hours and release that warmth, slowly, to the interior throughout the day and night.

In order to find out more about the unusual dwelling, MOTHER EARTH NEWS sent staffer Richard Freudenberger to Olympic Valley, California where–surrounded by several inches of snow and subfreezing temperatures–he talked to owner/designer Tom Smith (in a comfortably warm atmosphere) and questioned him on various aspects of the thermal envelope house including the all-important “passive” approach to its heating.


The number of solar houses being designed, built, and lived in grows by leaps and bounds every year. And, more often than not, these “newcomers” on the solar scene are passively heated. Let’s face it… if you’re building a house from scratch, why bother with pumps and pipes (which are not only expensive, but are also subject to periodic failure) when you can get the same results from a system that uses nothing but a well-planned design to achieve its goal?

Furthermore, “active” heating systems require a collector, something that [1] most likely will be commercially produced and costly, [2] will probably detract from the beauty of the house, regardless of how aesthetically pleasing the structure otherwise is, and [3] will usually necessitate additional engineering and construction considerations.

These factors helped Tom Smith and his architectural advisor, Lee Butler of San Francisco, decide to go with a totally passive system. And–after 20 months of research and a full year of living in the house–Mr. Smith has no regrets. If anything, the structure’s efficiency has exceeded his expectations … especially since many days are overcast in the Sierras, and even in bright weather the trees native to the area block much of the afternoon sun.

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