Thanks to their thick walls, Zurich's historic buildings are in some cases more energy efficient than their more modern counterparts. That's certainly the case if you compare them to 1960s-era constructions like the building that houses
ZURICH – Our newspaper had five Zurich buildings photographed and analyzed by German thermographics expert Bernd Schönbach. Three of these were municipal buildings, one new and two historic. The fourth was the office building occupied by Greenpeace. The fifth is the 36-story, 126-meter Prime Tower, Switzerland's tallest building.
The verdict: new "minergy" constructions don't do any better in terms of preventing heat loss than 17th or 18th century buildings do. And the Greenpeace building is anything but environmentally friendly.
"It's a typical 1960s building," said Schönbach aid of the environmental organization's office building. "Thin walls, and poor insulation – the concrete beams over the windows are particularly inefficient in terms of conserving heat." The images do indeed show a stronger presence of heat around the windows. Fine, pale yellow surfaces between stories indicate that the ceilings are made of concrete – "a no-no by today's standards."
Greenpeace may be forgiven for the architectural sins of the past. Staff behavior, however, is another matter. Not all staffers, the thermographics analysis suggested, seem to have a full grasp of their employer's ideals: at midnight, a window was open (the images were taken at night, in February 2012).
By contrast, the new district court building came through very well. Both of the historic buildings included in the study also proved to be quite well insulated – presumably because of their thick walls. Prime Tower was a harder read due to its glass facade. "On the lower floors what we're seeing is a mirror image of warmth coming from surrounding buildings, and if the upper floors look as if they aren't losing any heat at all it's because they're actually reflecting the sky. So it's deceptive," said Schönbach.
The Prime Tower is a good example, the thermographics expert explained, of why definitive pronouncements on the energy efficiency of any building can't be made from such photographs alone.
But what the experiment could establish, Schönbach said, was that buildings erected between the 1950s and 1970s – like the one that houses Greenpeace – were the worst in terms of energy efficiency. The biggest problem with regard to energy loss, he added, is the behavior of building users, not the buildings themselves.
Read the full story in German by Ivo Cukas
Photo – Google Maps
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