If the outside temperature is lower than inside then single hose is at least as good, as long as you open a window somewhere else so outside air rather than som

If the outside temperature is lower than inside then single hose is at least as good, as long as you open a window somewhere else so outside air rather than some other apartment’s air is sucked in Single hose portables are bad in countries where air con is practically essential, but are fine or even desirable for countries where only a handful of % of people have AC - the purchases will be for use cases like attics and top floor apartments where inside can be easily hotter than outside