A Striking Bohemian Geothermal Home
On the border between Austria and the Czech Republic, where the Iron Curtain once formed an imposing partition, one of the most unique nature reserves in the world boasts of having been populated and dramatically modified by humans since medieval times. This is an unusual point of pride for a biological sanctuary, but locals claim that the Třeboňsko Protected Landscape Area in southern Bohemia is a case study in harmonious coexistence between people and nature.
Tourists flock from neighboring countries to the reserve’s main town, Třeboň, but small clusters of houses on the town’s outskirts have remained free from tourists and untouched by development for decades. When Prague-based architects Martina Buřičová and Štěpán Kubíček were commissoned to build a new home in one of these outlying villages, their vision had to be tempered by the region’s longstanding architectural conventions. "The other houses in the village are historical ground-floor brick buildings with saddle roofs," Kubíček explains. "The village was practically inaccessible between 1948 and 1989. Due to this fact, there has been no new development during the last century."
Buřičová and Kubíček proved that creativity flourishes within limitations, designing a house that gracefully balances the town’s strict construction directives with the owners’ penchant for modern style and environmental responsibility. The structure was restricted to one level (with cellar and attic use permitted), elevated no more than 12 inches off the ground. It was allowed smooth, single- or double-color stucco on all exterior walls and a red or gray tile roof. Dormers had to be set more than 20 feet apart, with additional daylight coming from skylights set flush against the symmetrical saddle roof, sloped between 38 and 45 degrees.
Given these constraints, one might expect a staid result, but the 3,000-square-foot house lives up to its "Bohemian" identity: It is original, progressive, and largely independent of that behemoth of convention, the public utility. The region’s geothermal energy provides a natural, renewable power source, harnessed through three boreholes reaching 300 feet into the earth. The thermal pumps, in combination with solar panels, supply 90 to 95 percent of the house’s heat needs.
Geothermal power has been used since the early 20th century. In areas with significant subterranean steam activity and geysers, such as Iceland or California, energy can be distributed on a large scale through power plants dedicated to the renewable resource. Where steam is scarce, such as in Třeboňsko, geothermal pumps simply capitalize on the temperature differentials between the outdoor air and the earth several hundred feet down.
Buřičová and Kubíček included a system from Swedish company IVT called a bedrock heat pump. The device taps consistent warm temperatures from deep underground rock, transferring heat to the house by compressing a nontoxic fluid through hoses. Thermostats send signals to the pump in order to monitor demand and save energy. When the pump can’t do the job alone, an electrical boiler kicks in. Water for the house and pool is heated by solar panels on the roof of the garage. "Originally there was a plan to build a small water plant on the nearby river," Kubíček adds, "thus securing complete energy independence. However, this idea was abandoned due to the investment costs and complicated approval procedures." Nevertheless, the house is a model of efficiency in a village where alternative energy technology is scarce, mostly due to a lack of state subsidies, which ordinarily defray steep up-front costs.
In the process of creating this high-tech system, the designers also found room for low-tech solutions. The sloping site accommodated a day-lit basement and underground terrace—critical features in a home where the cellar functions as a primary living space. The basement houses a fitness room and sauna, plus heat-storage tanks that collect energy from the roof. In the upper reaches, the attic acts like a second floor, with sleeping quarters for the owners, whose parents generously gave up the garden of their neighboring house to provide a building site for their children and two young grandchildren.
While the design honors the past, it also looks ahead to a time when climate conditions may shift. The house relies primarily on just one resource—the sun—to provide energy from overhead and underfoot, so no matter our environmental fate, all that is needed to keep this place warm is a sunrise.