Each model features arched cathedral ceilings, and the absence of load-bearing interior walls makes for easily configured, or reconfigured, open spaces. Two years ago all the models were redesigned to increase the height on the loft-like second floors without enlarging the diameter.
Each house is assembled on a 12-foot- (3.6-meter-) square foundation. This small footprint means less area to excavate, and more vegetation can be left undisturbed near the perimeter.
On the foundation is installed a turntable-like structure and rings fitted with 1,600 stainless steel ball bearings. The turntable, driven by a one-horsepower (745-watt) motor, allows the owner to turn the house by push button or computer-programmed control. It can also be rotated manually.
All the mechanical services are grouped in a central shaft in flexible hosing that follows the house as it moves. This way, power and water can flow even while the house is moving.
Because of the high insulation levels (R-28 minimum in both upper and lower shells) and the natural convection induced by the shape of the interior space, heating and cooling needs are claimed to be 30 percent less than in conventional houses. Wood-burning stoves, forced-air furnaces, or electric baseboard heaters are options.
Dome-dwellers in earthquake-prone regions will also appreciate the structural stability of the shape. These domes can withstand seismic forces up to 8.0 on the Richter scale. Sunspace also claims that the dome shape helps deflect hurricane-force winds.
Exterior finishes are maintenance free; a standard 300-square-foot (28-square meter) copper cap and the absence of valleys and ridges are said to virtually eliminate potential leaks in the roof. Rain on the copper produces copper sulphate; this mixed with runoff helps prevent moss from forming on the wood. Over time, the copper acquires an attractive patina.
One Happy Dome-Buyer
A recent customer who was drawn to these characteristics is Joe Tufano, who lives about 60 miles (100 kilometers) west of Chicago on a five-acre (two-hectare), partly wooded site.
When he saw a Sunspace house nearing completion, he "fell in love with it." Tufano recalls: "The fact that it rotated was cool but it wasn't the first thing on my mind. I was more interested in the insulation properties, materials, and its construction." He bought the largest model, with four bedrooms, three full bathrooms and two half bathrooms, living room, dining room, and kitchen.
It took the Sunspace technician and three skilled workers three months to complete his house, which he describes as "pre-engineered" rather than "prefabricated." It is clad in split cedar shingles, which will weather in time to silver gray. On the inside is knotty pine for the walls/ceiling and an oak hardwood floor.
After living in the house for four seasons, Tufano reports that the house requires half the heating and air conditioning of a conventional house of the same size.
Adjusting to Spin
Life in a rotating house can take some getting used to. When he forgets that he turned the house before going to bed, Tufano can be startled in the morning by an unexpected view out the bedroom window.
A Sunspace house can easily be rotated completely or partially in just three minutes, at the push of a button. It can also be programmed to seek or avoid solar heat, depending on the season and heating or cooling needs. The house can be rotated so that a side with large windows is in shade when the weather is hot or in full sun when it's cold.
Inhabitants can watch the sun rise and set out the same window, and they can change their view any time. If their site is sloped, the vertical distance between an exterior door and the adjacent sidewalk will vary depending on rotation.
Tufano rotates his house for energy efficiency and "when I get tired of looking at the woods or the open space of the site from my dining room window, or if I don't like the way shadows are created inside during daylight."
Sunspace principal McCarthy says the company is planning to offer commercial as well as residential applications. They are negotiating a deal to build 1,000 to 2,400-square-foot (93- to 223-square-meter) rotating, open-concept, quick-service, stand-alone sandwich shops for a North American franchise operator.
The company is considering designing facilities for office and retail, bed and breakfast inns, resorts, lodges, and time-share units. Educational, religious, and medical institutions may also be attracted to the efficiencies in construction and energy consumption.
While one can see how sun-seeking rotation could be a benefit for residents, it's less clear how this would be useful in commercial applications.
Albert Warson is a Toronto-based freelance writer and editor who covers real estate development and architecture for North American publications.