We'll be publishing an article in our November 2009 issue looking in great detail at the Passive House standard and its relative novelty among North American architectural circles. In Europe, where Holmberg works, Passivhaus (as it is known there) has been making inroads for some time, and many leading architects have adopted the criteria for insulation and airtightness that define this sustainability strategy.

Holmberg designed four Passive House models in Stockholm, each with the simple vernacular style that features a symmetrical pitched roof and basic rectangular floor plan. The walls are constructed with super-insulated panels that stack like bricks, and clad in a dark plywood facade that resembles the architect's previous project with Smedshammar. The leak-proof skin will retain the heat generated by residents and appliances, dramatically reducing energy loads required to control indoor climate. It's typically said of Passive Houses that the entire space should be able to be heated with a hair dryer.

Holmberg partnered with Gösta Westerberg Energihaus to formulate the complete housing package that buyers will receive, which includes optional interior decorating services and products. According to the Gösta website, one of the four homes has been sold to date.

Keep an eye out for the Off the Grid section of our November issue for a story on two of the first Passive Houses to be built in the U.S.

For more interior shots and floor plans, check out Dezeen.