We are in the process of adding an AC system to the top floor of our old home (on the mid-Atlantic coast). Standard AC systems (with ducts) are not an option due to the configuration of the house/rooms with no realistic ductwork space. We have been told that a ductless mini-split system would be suitable for our home. However, I have one main concern about this. The floor on which we would be installing this system is fairly chopped up due to numerous walls and doors. I know that the min-split systems are designed to accommodate various zones but can one unit appropriately cool, say, two smallish bedrooms that are across the hall from each other? We would have three units installed on the floor but I am still stuck on viewing these systems as “permanent window units”, so to speak. A standard window unit can easily cool one room (and even make it very cold) but the air doesn’t flow well into other rooms, leaving one room very cold and adjoining rooms very warm. Do the mini-split systems (with inverter technology) truly work differently? In short, would we basically have a permanent window unit that will make one bedroom very cold while the bedroom across the hall is warm? Or does the inverter technology change the ability of this system so that air flow between the rooms can effectively cool both? We also have transoms that can be open at all times, as well as doors directly across from each other that could be open during the day. The cost would prohibit having a mini-split unit in every room, as there are four bedrooms and a number of other smaller rooms.