The Triesch House in Berlin: How Aerogel Insulation Made a Slim, Modernist Home Possible in a Cold Climate

The Triesch House: When a California Dream Met Berlin Winters – Thanks to Aerogel

In the heart of Berlin’s Charlottenburg district stands a house that looks like it was airlifted straight from the hills of Los Angeles. Clean lines, warm mahogany cladding, floor-to-ceiling glass, and impossibly slender concrete columns. Yet on a February morning when the temperature outside is –12 °C, the thermostat inside reads a steady 22 °C – with almost no heating required.

The secret behind this small miracle? Walls that are only 20 cm thick, insulated with aerogel – the lightest solid material on Earth.

For decades, extreme energy efficiency meant one thing: thick walls. In Germany, a proper passive house often demands 40–60 cm of insulation. In northern China, it can reach 80 cm. The result? Lost interior space, deep window reveals, and a visual bulk that clashes with modernist ideals of lightness and openness.

Architect Lars Triesch refused to accept that compromise. Inspired by the post-and-beam masterpieces of California’s Case Study Houses and Ray Kappe’s floating structures, he wanted a Berlin home that felt airy and transparent – without freezing its occupants.

Aerogel made it possible.

With a thermal conductivity of just 0.013–0.018 W/(m·K) – roughly three times better than conventional insulation – aerogel delivers the same performance in a fraction of the thickness. What used to require 1990s-era 40 cm of mineral wool or EPS now fits comfortably inside 20 cm.

How They Did It

The Mahogany “Sandwich” Wall A 15 cm laminated mahogany panel is wrapped around a 3–5 mm aerogel blanket on both sides. The total wall thickness: 20 cm. The measured U-value: 0.18 W/(m²·K) – easily beating Germany’s strict passive-house requirement of ≤ 0.15 while looking like fine furniture from the outside.

Skinny Concrete Columns That Still Insulate Structural columns were reduced from the usual 30–35 cm down to 18 cm by embedding a 5 mm aerogel core and reinforcing with carbon-fiber bars. The columns are stronger than traditional ones and eliminate thermal bridges completely.

Windows That Don’t Leak Heat Aluminum window frames received aerogel-filled thermal breaks, dropping their conductivity from ~1.8 W/(m·K) to 0.8. Paired with triple low-E glazing and warm-edge spacers, the entire window assembly hits a U-value of 0.78 W/(m²·K).

A Roof That Breathes Instead of thick PIR boards, the pitched roof was sprayed with 20 mm of aerogel coating under the metal standing-seam skin. No condensation, no heat loss, and 3 °C cooler attic temperatures in summer.

Three years of monitored data tell the story: annual heating demand is 28–32 kWh/(m²·year) – roughly half the average for new Berlin homes of similar size. Interior usable floor area increased by 4–6 % simply because the walls are thinner.

Beyond One House: Aerogel Goes Mainstream

What was once a €300–400/m² exotic material used on Mars rovers and oil pipelines is now dropping below €150–180/m² thanks to ambient-pressure production breakthroughs by BASF, Cabot, Aspen Aerogels, and a wave of Chinese manufacturers.

Prefabricated aerogel panels are now factory-made to ±1 mm tolerance, cutting on-site labor by 30–40 %. Cities from Paris to Shenzhen are testing aerogel retrofits on historic façades that can’t be thickened externally – preserving architectural heritage while slashing energy bills 35–50 %.

The Bigger Picture

Lars Triesch puts it simply while standing on his rooftop terrace overlooking Berlin’s snowy treetops:

“Aerogel didn’t just save energy. It gave me back the proportions I dreamed of. For the first time, extreme performance and architectural elegance aren’t enemies – they’re partners.”

In an era when buildings must become nearly zero-energy without turning into bulky bunkers, aerogel is proving that high performance doesn’t have to look heavy.

The future of sustainable architecture isn’t thicker walls. It’s smarter, thinner, lighter ones – and it’s already here.