Affordable net zero: foam in, air conditioning out
By prioritizing energy minimization, and taking a pragmatic approach to materials and insulation, client Dr. Jung Soik and architect Yang Soo-in of Lifethings were able to construct a net zero energy house, or one that produces more energy than it uses, on a reasonable (if not meager) budget. Upon completion, Dr. Jung had spent US$284,000 on Sosoljip, the house which now stands at a fishing village four hours to the south of Seoul, South Korea.
According to Lifethings, Dr. Jung first became interested in self-sufficiency while studying in Milan, when a drivers strike to protest the price of oil made fresh produce hard to come by. Pondering the "vulnerability" of the support systems and supply lines that grease the wheels of society, Dr. Jung began to think about self-sufficient communities. Sosoljip, then, was a first practical step towards just such a community; and Lifethings was commissioned to design it.
"The client and the architect wanted Sosoljip to be based on common sense in its design, construction, and budget," Lifethings writes. The sensible budget was not so much borne out of necessity, but a proof of concept that sensible, net zero design needn't be prohibitively expensive.
Lifethings first priority in designing the house was energy minimization, with a particular focus on insulation – "the most important factor." To this end, the entire reinforced-concrete structure is encased in 20 cm-thick (7.9 in.) Styrofoam, a dense brand of polystyrene foam, the generic insulating properties of which make the material a popular choice for disposal coffee cups - or used to.
That insulation topped the hierarchy of properties precluded shingle or panel exterior surface finishing, since its installation would inevitably damage and perhaps compromise the performance of the insulation itself. Instead the architect turned to polyurea spray which forms a relatively tough, waterproof surface. Windows are kept to a sensible proportion of the surface area so as not to undo the good work done by the insulation.
The house is fitted with both photovoltaic and thermal solar panels, with a wood-burning stove for back-up. The house does without mechanized air conditioning. The on-site renewables lack the heft to run it, and in any case, Lifethings writes, "the client will gladly wear sweaters in the winter and sweat a little in the summer, which is only natural." The 230 sq m (2476 sq ft) Sosoljip will be shared by Dr. Jung and her parents, and includes both separate and shared living spaces for both.