Hot under the collar
Glass Times editor Nathan Bushell reflects on a recent story that called for a ban on glass skyscrapers.
Should glass skyscrapers be banned?
According to Simon Sturgis, chairman of Riba’s sustainability group, and an advisor to the government, whose opinions featured in a recent Guardian story, all-glass skyscrapers should be banned because they are too difficult and expensive to cool.
“If you’re using standard glass facades you need a lot of energy to cool them down, and using a lot of energy equates to a lot of carbon emissions,” Simon said.
According to the story, The International Energy Agency estimates that about 40% of global carbon dioxide emissions come from constructing, heating, cooling and demolishing buildings. Air conditioning is a growing proportion of this: energy used on cooling has doubled since 2000 and accounts for about 14% of all energy use now.
This goes against my understanding of glass designed for large glass facades; just as units can be made to trap and retain heat, they can also be designed to reflect the heat while remaining clear.
Technological advances have also led to reactive glass that turns opaque in bright conditions, and we have reported recently on research into windows generating electricity.
However, these products are often made from laminate glass, which come with their only environmental problems, according to Simon.
“To mitigate the amount of energy used to cool these buildings, you have to produce a really complicated facade, which is usually triple glazed,” he said. “But double glazed units and laminated glass don’t last very long – 40 years or so. So you have to replace your facade every 40 years, that’s also not a very good idea.”
The story paints a picture of a warming world building greenhouses inside greenhouses, which is not the image that the glass industry will want to portray.
My first thought was that if you came up with any building material, someone will happily give you a list of its environmental impact.
However, I know that much is being done in the glass industry not only to mitigate any negative environment effects but to also offer solutions that help create sustainable buildings.
I would love to hear your thoughts.