What Is A Passive Building?

welcome to our new crib in brooklyn

Back in 2002, Oeuf was hatched — it’s hard to imagine now, but at the time there were no other kids brands producing modern furniture or making clothing in natural materials and colors. Time flies when you’re having fun, and we can hardly believe our brand turns 20 years old this year. 


And now in 2022, we’re finally building a fitting nest for our egg. In Brooklyn’s Prospect Heights, we’ve been quietly working on a new office building that follows the Passive House standard, one of the world’s most aggressive and proven approaches to radical energy reduction. Passive buildings use 90 percent less energy to heat and cool, thanks to being virtually airtight, extremely well-insulated and primarily heated by solar heat gain and the people and appliances inside them.

Working with architects Bangia Agostinho, the space features triple-pane windows, cellulose insulation in thick walls as well as new solar panels. All passive buildings must adhere to these 5 Passive House principles:


  1. Triple pane windows — In addition to improved insulation, these also improve soundproofing, an added benefit on a busy city street.
  2. Quality insulation — Our office uses cellulose insulation, which is fire-resistant, eco-friendly and effective, though hard to apply. Our walls are 12 inches thick, the maximum width suggested for passive buildings.
  3. Airtight construction
  4. Ventilation with heat recovery
  5. Thermal-bridge-free design


“It’s full-circle for us,” says co-founder Sophie Demenge. Oeuf, known for having paved the way in modern design for children, now hopes to pave the way for how construction should be done — to the highest standards of sustainability. It just makes sense, for the planet and economically. She and husband Michael Ryan design all Oeuf furniture together, and Sophie the clothing, and applying their design principles to the office as well has been a natural fit: “A dream.” (Note: Sophie and Michael’s daughter Mae turns 20 this year as well. She was the muse that started it all!)

We’re lucky to partner with brands we love to decorate the space, including Ressource paints, vintage Upstate Rugs, linen from Rough Linen, Reform kitchen cabinets, wallpaper from Farrow and Ball, rugs from Tamar Mogendorff, Josef Frank wallpaper and furniture from Cody Campanie. We’re still putting the finishing touches on the decor, but stay tuned for the big reveal later this year.

Besides making sustainability a natural part of everything they do, Oeuf’s founding couple also prioritized the office’s walkable proximity to their home, where they live with two kids and four rescue pets. Living and working in the same neighborhood means a work-life balance with intention, so the last Oeuf office was close by, too.

“The idea is to feel good inside and out,” Sophie says. “Inside, with the clean air of the building, the peace and quiet of the triple-pane windows and knowing we are making choices in accordance with our beliefs. And outside, inspired by this vibrant neighborhood surrounded by art and nature, good food and good neighbors where there is a true sense of community.”

We’ve been so eager to share this project with you, as it’s been in progress for years now (with no help from pandemic supply chain delays). Earth Day seemed like the perfect time to give you a peek — and hopefully it can inspire your own project, now or in the future.


“We hope the story behind our office inspires many others to go passive!” Sophie says. 



Founded in 2002 by French-American couple Sophie Demenge and Michael Ryan, Oeuf designs children’s furniture, clothing and decor. All designs are ethically and sustainably produced by skilled artisans and craftspeople, many of whom have partnered with the brand for up to 20 years. Oeuf is pronounced “uh-f” and means “egg” in French.