As someone who also lives in Toronto: most things being built now are giant class towers.

Now, glass sucks at insulation (even triple glaze), but—depending on the coatings—it lets in a lot of sun light and with that potentially heat.

While in a perfect world there would be no / minimal exchange between the inside of the structure and the outside,† being too warm may be better than being too cold, as I'm guessing that it's easier to throw away the 'free' heat of the sun away than introducing it in winter. Certainly heat pumps can go either way, but I figure that it's easier to dump it.

† The entire point of "buildings" are to be environmental separators after all.