Replacing air conditioning: split or packaged?

[weyes2013]

I've only just discovered that central air conditioning comes in two forms, split and packaged air conditioner, and I guess we must have the latter.
Our architect had an A/C contractor look at our system to advise us on replacing it (primarily regarding placement of ductwork) during a home renovation project, and he didn't find an air handling unit (some of the A/C guts and ductwork are sealed in the attic and more or less inaccessible).
This is an issue because our architect is trying to figure out where to put an AHU for a split system, but now I'm wondering if we even need one? Can we replace our old system with another packaged system? What are the reasons to go with one over the other? Are there big differences in cost, efficiency, noise? Are any particular brands considered better than others?

[nevinjohn]

Packaged air conditioner is not a centralised system, but looks like one. In your case, the unit (ceiling suspended) would generally be hanged in toilets or store rooms. When you switch on the unit do your hear the noise in washrooms/ stores? That is the place where you have to look for the unit.

If you cannot find it, package units are generally installed on terrace, and ducted. So, you can find it there.

If that is also not possible, locate the outdoor unit (the condensing unit). Locate the refrigerent pipes and see where it goes to...