Most high rise office buildings use steam (older bldgs) or heat strip for heating. If there's an electrical problem, all fans blowing the treated air stop. They use chilled water flowing through air handling units for A/C. (in winter, these same units supply the heated air, the flow of chill water is usually halted.)
In a system like this, if the AHU stops for any reason, the whole floor is effected. Since chillers and associated equipment are very expensive, I would imagine the maintenance fees would be uncomfortable. (get it? Sorry.)
I think maybe spread out across all owners it might be palatable. You have to figure, if your heating/AC conks out, you're into that for 20k. So that's a pretty decent number when/if you're talking about multiple flats on one floor, right?
Every big building I ever lived in in Chicago had this system but for residential use. I am sure it is expensive when it breaks, but it is also amortized across hundreds of units. I'd go so far as to say it's "industry standard" so isn't going to be much of an obstacle for converting office buildings to residential spaces.
(In NYC, we all agreed to believe that there is no such thing as residential air conditioning that is not in the form of a window unit, however.)
In a system like this, if the AHU stops for any reason, the whole floor is effected. Since chillers and associated equipment are very expensive, I would imagine the maintenance fees would be uncomfortable. (get it? Sorry.)