Near Paris, a Lesson in Passive Solar

In Bessancourt, a town in Ile de France just 28 km northwest of Paris, Karawitz Architecture has abstracted the traditional form of a farmhouse and given it new life as a passive solar home.

Its exterior membrane is clad in bamboo. Inside, it’s all bare wood.

“It was important for us that there were raw but real materials inside, because of their tactile, acoustic and olfactory qualities,” Karawitz’s Milena Karanesheva said. “The house actually smells very good, due mostly to the wood.”

The clients, a family with two children, sought energy savings, ecological materials and contemporary design. And they wanted to live near nature without the necessity of using a car.

The architects designed their home to slip into a site near a town center with12th century-church, public library, town hall and train station – all lined up next to Montmorency Forest. It’s in the most populated region of France, with 11.7 million of the nation’s 82.8 million inhabitants.

Karawitz is a small French firm with big ideas for sustainability. Their design is the first certified passive house in Ile de France and the second in the nation. It uses a slim sum of 177€ Euros for heating each year. The architects achieved the savings through 27.5 cm-thick insulation, triple-glazing, very tight air ventilation, and heat-recovery of 76 percent.

“The real economic savings will come in the next 10-20 years,” Milena said. “After that the house will be cheaper than the same house constructed in an ordinary way.”

It’s oriented to the south not just for the sun, but because of local building regulations. “The wide openings were allowed only on the southern exposure,” Milena said. “In the other directions, the openings were possible only because there are behind the bamboo cladding.”

Their plan is simple and strict, with all rooms on the south side. The living room is divided in two parts by a folding wall, so the space can change with use.

The design is about simplicity and subtlety. A rectangle with two slopes, the architects covered the form with one material for walls, shutters and roof. To make it look less voluminous, they chose bamboo, native to the region.

“First we thought about wood, but then we did a lot of samples and there were still a bit too heavy,” Milena said. “On the other hand, there are a lot of bamboo fences and railings in the suburbs of Paris. Bamboo is very common material, but always for secondary uses. A lot of it becomes a beautiful gray and we thought that we should try to use it to cover the façade.”

And so they did – for an effect that offers screen, shade and transparency all at once.

For more on Karawitz Architecture, go to http://www.karawitz.com/