Hot air is lighter than cold air, so the hot air in area rises up to the top of the area. Some ac unit manufacturers state they sell portable airconditioners that don't require fresh air. The heat that is produced on your conditioner is as heat load a person can term it as heat regain. Your AC is to be able to circulate the air through house easily.
One big power gobbler is setting your thermostat to 68 degrees once summer hits or 80 in the winter. All portable air conditioning units need to vent the air they remove to the room tend to be cooling. Some features may not necessarily needed inside your situation. The manufacturer offers a five year warranty for your portable hot tub. Unlike split a/cs they easy to to maintain too.