The ductless HVAC units are called mini-splits.  They are only good for single rooms -- so 1 per room. They DO require a hole in the wall to drain outside and there is an exterior compressor. They provide heating and cooling and are really designed for climates that do not have extremes of temperature -- if you  have 100 degrees and 90% humidity it's not going to cool well. If you have 0 degrees it will not heat well.