If a ship has a thousand cabins, that means a thousand fans, a thousand heat exchangers, and how many miles of pressurized pipe and air ducting.
Yup, and this is no different from the miles of electric wiring, toilet plumbing, and other utilities installed to service the 1000 cabins. Actually, there probably needs to be two pressurized loops, one for cooling and one for heat in order to have full climate control. That piping probably runs in the same conduit routes as the electric.