Japan's first Passive House

In the last 10 years more than 15,000 buildings in Europe, from single family residences to entire factories, have been built or remodeled to the passive house standard. This means that, among other factors, these structures use 90% less energy, and it’s done, for the most part, by simply better utilizing the natural resources of the surrounding environment. To begin with, a passive house is virtually airtight. It’s also equipped with an energy recovery ventilator that provides a constant, balanced fresh air supply, minimizing energy losses and providing top rate indoor air quality. Furthermore, instead of relying on active systems to bring a building to zero energy, passive houses use natural resources like sunlight, for example, and apply them efficiently.

Buildings that meet the passive house standard are popping up all over the world, but only recently has Japan finally built their very first passive house in Kamakura, a small city 30 miles from Tokyo.

A cross section of the wall and window.

The home wasn’t originally intended to be passive, but site constraints like a tight budget (the land itself was over $3,000/sqm), the client’s demand for only electric power and the humid, sub-tropical climate forced the project in that direction. There was also Japan’s strict earthquake requirements, which call for rigid, load bearing walls instead of an open diffusion wall. With all these factors to take on, the building was eventually headed up by Germany’s Passive House Institute as a pilot project for homes built in warmer regions. Learn more about passive houses.