It's fairly common in Arizona. A number of the apartment complexes use centralized water heating/cooling that is piped through all the apartments and is used fo

It's fairly common in Arizona. A number of the apartment complexes use centralized water heating/cooling that is piped through all the apartments and is used for the HVAC system. They usually flip the HVAC to heating mode during the winter, and cooling mode during the summer. It's a lot more cost-effective than having a different HVAC system in every single unit. This is especially true in Arizona, where it's not uncommon to hit temperatures of 110-120f in the summer. The downside is that if you have a hot day in the winter time (which isn't uncommon in AZ), you are out of luck because your HVAC is stuck in heating mode until March rolls around. Another downside is that the air conditioner will often struggle to cool things down to lower than 80 degrees during the summer time. I make do by supplementing the main A/C with a 10,000 BTU portable window-vented A/C, though... Which is free to use because electricity is included. So it all works out.