A closer look at Telus Sky: Can an all-glass tower really be considered green?
In Calgary, they measure the temperature in Celsius; on TreeHugger, we use Fahrenheit. However there is one temperature where they both meet, at -40 degrees. That's how cold it can get in Calgary in winter. When we first showed the Telus Sky Tower, designed by Bjarke Ingels Group with Canada's DIALOG, I noted that "There is not enough information to tell exactly how this building is more adaptive to the very cold climate of Calgary; It looks like a lot of floor-to-ceiling glass, with extra surface area and corners by all that jogging of the facade at the top."
Since then, more renderings have become available and it raises the question again: Can an all-glass building really be green? Telus sky is going for LEED Platinum, and projects energy savings of 35% compared to similar size developments, but look what is going on here: every single residential unit is projecting a corner out that has a deck on top and a soffit below, three additional surfaces exposed to the weather. The architects have gone out of their way to increase the surface area of the building, including the toughest condition any architect and builder has to deal with: terraces on top of occupied space, for every unit yet. It's ingenious, and gorgeous, but it is a thermal nightmare.
Renderings are just that, representations and not reality, but where does the insulation go? Those are not the usual radiator-fin balconies but enclosed space requiring insulation, waterproofing and a walking surface on top. Judging from this interior shot that shows the floor extending right out onto the balcony, it isn't on the outside of the slab; judging from the flat ceiling in the unit, it's not on the inside.
And of course, besides the jogging, it is floor-to-ceiling glass. Alex Wilson of BuildingGreen has noted:
A growing body of experts in sustainable design argues that our architectural aesthetic should evolve away from all-glass façades.
In the end, it is all about sex. Ingels describes the shift from a smooth skin on the lower offices to the jogging of the upper residential:
The large floor plates for workplaces recede to achieve the slender dimensions of residential floor depths. The texture of the facade in a similar fashion evolves from a smooth glass facade enclosing the work space to a three-dimensional composition of apartments and balconies. The resultant silhouette expresses the unification of the two programs in a single gesture – in rational straight lines composed to form a feminine figure.
Building scientist Ted Kesik can throw around the imagery too, talking about thin glass walls:
As a building scientist, I look at buildings the way a doctor looks at a body: I say ‘Ah, it may look sexy but boy, that’s not very healthy. I don’t know if I’d want to be that thin.”
TELUS Sky/Promo image
Sure, you can get to LEED platinum in an all-glass building, and you can design it to use 35% less energy than the crap we used to build before we cared about energy conservation. But is it the right thing to do? Should every apartment have triangles of floors, walls and ceilings exposed to Calgary winters as well as a floor to ceiling glass end wall?
The building is handsome and sexy, just like Bjarke. But this is Calgary, and you need a warm jacket in winter.