there are some things that you will need to consider before installing a split type aircon.

1. room ventillation - only rooms that have sufficient air removal and make-up are suitable for split-type ac units. the removal of carbon dioxide rich air (by means of extraction/exhaust fans) and supply of fresh outside air are a must. failure to do so can lead to the accumulation of carbon dioxide in the enclosed room. in a window type ac this is already built into the unit, there is always some air from the room that is blown out through spaces in the internal ducting, and there is sufficient make-up air drawn in through the hole thru which the blower shaft goes through. there is no such thing in a split type unit. so if you are going to stay in that room, especially if you are going to sleep in it, think twice.

I have a personal experience on this. we had a split type ac unit in one of our offices on one of the rigs i was on. everyone in that office always felt dizzy all the time, me included. when measured the O2 level was down to 15% and the CO2 level was up to 6%.

2. cleaning - remember that in most installations of split type units the evaporator needs to be removed for cleaning, just like cleaning the ac evaporator in your car. make sure you factor in this added expense, something those sales agents will not tell you. now if you can make provisions for easy cleaning (like say extra big drains, easy accessible location) then why not go ahead.