I've got a sanyo split system in our loft conversion bedroom. The unit is about 5 feet above the bed and I can easily sleep with it in quiet mode. The system was about £400 and I mounted everthing myself.

Then you need a specialist to come to plumb and purge the pipes. Probably cost £150 for that.

Makes the room ice cold in about 15 mins when set to quiet mode, takes about 2 mins when flat out.