Why Buildings Shouldn't Be Made of Glass

They can turn into ovens and become uninhabitable.

A closeup of a glass apartment building

Grand Warszawski/ Getty Images

A few years ago, a friend bicycled past a building under construction (not the one shown above) and tweeted:

"Happy to see more housing going up in SF. Not sure the new owners of these $$$$ condos will appreciate living in a solar oven though... (all glass, solid thermal bridge detailing and full western exposure.) Yikes!"

Now don't get us wrong, we love solar ovens here at Treehugger—but for cooking, not living. Another friend noted it would be "uninhabitable by 2050." He was wrong: It was uninhabitable by 2020.

The condominium association sued the developer and others responsible for the design and construction of the project. According to the press release from lawyers Berding & Weil, the glass curtain wall system "failed to include sufficient ventilation, which led to unhealthy temperatures within the condominiums." The law firm got a $10 million settlement for the condo owners. The settlement also bars the naming of the development or developer, which is why we are not naming any names here, and are just quoting the lawyer's press release:

“The building’s condo owners discovered that the west and south-facing units often became uncomfortably warm, as the sunlight struck their glass walls,” said Steve Weil, one of the founding partners at Berding & Weil, commenting on the case handled by partners Dan Rottinghaus and Scott Mackey. “We found that the condominium’s inadequate ventilation failed to purge the heat from the units. We further demonstrated that on sunny days when the outdoor temperature was mild the units could get as hot as 90 degrees without the ability to cool off, making the interior environment of the units unbearable.”

What is so interesting in this rapidly heating world is the defense position. The California Building Code requires that "interior spaces intended for human occupancy shall be provided with active or passive space heating, ventilation, and air conditioning (HVAC) systems capable of maintaining an indoor temperature of not less than 68 degrees."

But so many codes were written before air conditioning was common, and there are still some people who claim that it is a luxury. The defense argued that since there was no maximum allowable temperature specified in the code, there was no defect. So the lawyers went around the building code, and explain:

"Given the absence of a clear violation of California Building Code section 1204.1, Berding & Weil advanced an aggressive and successful plan to demonstrate that inadequate ventilation, and the long-term exposure to excessive heat, caused an uninhabitable interior environment within the units. Under Civil Code section 897, Berding & Weil proved that this design defect constituted “damage” as defined by Civil Code section 3281 (loss or detriment) instead of property damage. With this extraordinary recovery, the association now has the financial freedom to decide on the best possible fix to allow the residents the full enjoyment of their homes."

My nameless friend says this is a huge deal. "There are also dozens and dozens of all-glass buildings going up here in SF now and I keep shaking my head that @SFenvironment [San Francisco's Environment Department] hasn't flagged this. (I'm so appalled by the lack of exterior shading action here in California, where we HAVE SUN!!"

She also notes that because of this court case, architects and developers better start paying attention. She wonders "why the code isn’t working for us, why architects aren’t paying attention to this, but will now have to if they want to remain insured, and also how decarbonization that only focuses on electrification will be disastrous without envelope & shading retrofits because of this."

Nice Shades

Bris de soliel at the Salvation Army
Bris de soliel at the Salvation Army by Le Corbusier.

Lloyd Alter

Treehugger has been showing buildings with exterior shading for years, under the headline "Nice Shades." The virtue of them is you keep the heat out before it gets in, instead of spending serious money on air conditioning to remove the heat after the fact.

Exterior shading devices were common on buildings before air conditioning became common. Le Corbusier's Salvation Army Building in Paris was an all-glass building that overheated; he renovated it by adding Brise Soliel to shade the glass. They fell out of favor because it was cheaper just to add more AC.

A closeup of space frame window covering
Universidad EAN in Bogotá, Colombia by William McDonough & Partners.


Architects like Bill McDonough are using Brise Soliel today, to keep out the sun while allowing for natural ventilation. It is on a university building in Bogota, which has a temperate climate like San Francisco's, and thanks to the shading, gets by with natural ventilation.

Black shades on New York Building
Shades on a New York building.

Lloyd Alter

Air conditioning is now pretty much standard on new buildings, even in cities like Vancouver and Seattle that didn't use to need it. But even in buildings with AC, like this one in New York City, architect Stas Zakrzewski built nice shades around the windows to reduce solar gain. This may well have to become standard practice in cities.

shading on building
Shading at 8 Octavia by Stanley Saitowitz.

Lloyd Alter

My friend in San Francisco notes that because of the condo court case, architects and developers may finally be forced to stop building all-glass towers. They might have to start considering shading like Stanley Saitowitz did on his 8 Octavia building in San Francisco. Because the world is getting warmer, and we can't just keep throwing lots of air conditioning at these buildings: We have to stop the sun before it gets in. After this lawsuit, it is likely that developers and architects will sit up and take notice.