Station Park | 18, 28, 36, 43, 50 fl | U/C

[tomh009]

It's a whole building switch over? I didn't think anyone built buildings like that anymore. All the Momentum buildings allow for some units using AC simultaneously with some using heat. I talked to their construction manager and didn't believe anyone still built new buildings where it was a simultaneous changeover.

Yup, whole building.
That’s interesting - a friend of mine lives in Charlie West which is a Momentum building and they do a whole building switchover as well. I believe a friend of mine who lives at Garment St Condos said they had to wait for a certain date to use their air conditioning as well. 
My assumption was all buildings that didn’t have individual AC units on their balconies would be subject to a whole building switchover.

You can build a building with a single-loop system (switchover spring and fall) or with a dual-loop system (separate heating and cooling pipes, no switchover). The dual-pipe system will cost somewhat more (don't know how much), and will cost somewhat more to operate (as both heating and cooling systems will need to run simultaneously).  So, yes, single-loop systems are still being built.

The unit air handlers frequently have an auxiliary heat function to allow for some (electrical) heating when the building is switched to AC, but that heating is quite weak.