Vancouver’s growth by the real numbers.

via Vancouver’s growth by the real numbers.

I was impressed by one of the comments  by Randy Chatergee on this article which explains why these residential megatowers are not sustainable. I post it below.

No credible authority would ever do research on the sustainability of glass and concrete towers because the idea is so patently ludicrous. Certainly engineers and architects the world over are trying to build “green towers,” with double walls, SIP panels, PV surfaces, and the like. A decade ago an Austrian power company attempted to build a Passivehaus-certified 11-storey tower, but failed despite an enormous budget and a decent geothermally-suitable site. There are tens of thousands of low- and mid-rise Passive Houses in the world today.

The fact is that concrete as a building material has the highest embodied carbon of all building materials and the second highest thermal transmissivity, after glass. The building envelope of the newest towers with triple-pane, argon-filled, low-e windows–there are none in Vancouver–cannot claim an R-value over 3, as compared with a poorly-built R2000 home that in practice easily meets an average insulation value of R15. Many towers test out at far less than 2 because protruding balconies act as heat fins. Add also the differential thermal gain of the different building aspects, and you have a nightmarish HVAC problem year around, and one that can only be cured with huge energy inputs to move the heat and cold around and outside the building. Consider the fact that elevators require accelerating a 5 tonne weight (cab and counterweight) hundreds or thousands of times a day to 3-10 m/s. Finally, glass wall construction is rated to last 20-30 years before a full building envelopment replacement will be required.

Both the built cost and operating costs in terms of carbon and price per usable square metre are so far beyond almost any other housing style that no one would or could ever claim towers could ever be sustainable as a housing form. OK, one Vancouver mayor tried, and he lasted one term. His claim was so thoroughly debunked and the idea of ‘ecodensity’ through point towers so thoroughly discredited that the only engineering company that defended it was soon out of business.

The only shred of truth in the debate on density is that higher urban densities do tend to encourage lifestyles OUTSIDE the home that are less carbon intensive than some suburban densities. However, there are far too many confounding factors at play, including land use patterns (proximity to work/stores/school, etc), relative wealth, and culture, to be definitive about every neighbourhood everywhere.

Simply look to areas on earth where energy costs are high relative to the standard of living, and you will see no residential towers. That should be proof enough. Consider also that mid-rise developments can meet or exceed tower densities due to setback and separation standards, so even the very tenuous lifestyle factors cannot be used to defend towers over more sustainable low- and mid-rise structures.

The facts could not be more clear. Living in a glass tower is a luxury conceit every bit as ecologically devastating as a McMansion. Both these forms of development are climate crimes.

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