I just left a 3 story walk up with central air and I can say the during the summer the large roof mounted AC units (technically split systems as you describe them) drove me absolutely insane. The humming caused by multiple machines running made it almost impossible for me to stay at home and fall asleep.<p>I&#x27;m sure there are smart mechanical engineers working on vibration free AC units, but until then  I&#x27;m looking for a house.