One Victoria | 63 m | 19 fl | Complete

[modernizt]

I've read that all-glass building envelopes are actually kind of problematic for all sorts of practical reasons (e.g. energy efficiency).

A lot of that was information fed to the press by the not-glass-segment of the construction industry. I pointed out, for example, that in Europe the highest levels of energy efficiency essentially demand a glass enclosure on the building, which is the exact opposite of what said lobbyists were claiming.

What are you talking about? Glass offers almost no insulating value, and insulated spandrel panels still don't come anywhere close to the thermal/insulating performance of an insulated solid wall system. (And yes, lobbying is always a part of these discussions but that goes both ways. It's completely fair for opinions against window-wall's abundant use - many of which come from building scientists - to be present in the discussion.) There are ways glazing can be used to benefit a building's environmental performance but it depends on the orientation of a building on site and the % of the exterior envelope being glazed. To say that glazing is a boon to uber-sustainability is a complete misnomer.

Before the misinformation gets too far in this thread - let it be known that glazing systems are weak in terms of thermal performance. That said, there are many ways to mitigate this using the latest building science advancements, and like much of architecture, decisions often fall in the grey area between matters of sustainability/energy efficiency and other architectural concerns such as aesthetic, feel of the space, light, ventilation, tectonics, etc. etc.

So, no, it's not as simple as "glass is bad". But glazing systems do indeed fall short of many alternatives when it comes to energy performance of a building.

City Centre has a number of solid insulated wall areas as well as large areas clad in spandrel glass from what I remember seeing (I'll have to peek into the thread), but a fair bit of it is clad in window wall (which is generally a weaker system than curtainwall when it comes to performance / heat loss / thermal bridging / lifespan). One Victoria seems a fair bit more conservative in terms of glazed area, however I feel as though all the spandrel glass at the top hurts its appearance. 

Remember that in Ontario now, a 60/40 solid-to-glazed ratio applies in the building code, so you will see less vision glass on new construction and more spandrel glass, as well as (hopefully) more buildings that embrace an architecture of solid walls with punched-out windows in ways that are architecturally pleasing. A lot of architects rely on spandrel glass to create the all-glass aesthetic many of us have come to love, but unfortunately spandrel glass often looks crappy and it doesn't offer the insulating value of a solid wall, so it's often lose-lose in my opinion.