Maybe it will be a weird question... but...
A single hose portable air conditioners are inefficient, as they take the air from the room and remove it using a hose, some air is cooled down and returned to the room...
Ok... so why does it work like this? Why the hot air is removed at all??? It would be easier to take the air, cool it down and that's it, nothing should be removed from the room :)
Lets consider dual hose units... why do they take the air from the outside at all (sometimes it is hotter than the air inside of a room)? Why doesn't they work using air from the room only?
