Wright's Solar Hemicycle

When the Jacobs family outgrew Frank Lloyd Wright's first house for them, they did something that almost no client has ever done: they went back to the same architect for a second commission. And Wright responded not with a refinement of what he had built before but with something completely different, an experiment he had been wanting to try for years.

The result, built in Middleton, Wisconsin, between nineteen forty-six and nineteen forty-eight, is what Wright called a solar hemicycle. The term describes its shape and its logic. The house is semicircular in plan, its curved wall of glass and stone facing south into a sunken garden. The northern side of the house is buried into an earthen berm that acts as natural insulation, sheltering the living space from winter winds. The roof curves overhead, its overhang calculated to block the high summer sun while admitting the low winter sun deep into the interior.

In other words, it is a passive solar house, designed not with mechanical systems to heat and cool it but with geometry. The shape itself does the work. Wright had been thinking about solar orientation in architecture since the nineteen-thirties, and the Jacobs second house was his first full articulation of the idea at residential scale. It is considered one of the earliest examples of an intentionally passive solar residential design in modern American architecture, building on experiments with solar-oriented homes that began in the nineteen thirties.

Katherine Jacobs later wrote that the house was genuinely difficult to live in at first. The learning curve was real: the sod roof needed tending, the stone floor retained heat but could feel cold on cloudy days. But the house also worked as promised in ways their first house never could, using almost no purchased fuel in an era before energy costs made that a common concern.

Like the first Jacobs house, this one was listed on the National Register of Historic Places in nineteen seventy-four and declared a National Historic Landmark in two thousand three. Together the two houses form a kind of biography of Wright's domestic thinking across a single decade, told through the needs of one ordinary family.