I assume when you say this you are talking about the kind with the 3" vent hose you pop out a window to exhaust like the DeLonghi Penguino or the Haier models?
Assuming this is the case we've had one or two kicking around the office for going on 10 years now and both units are still working well... which either speaks to the longevity of the things or how rarely they get used. <.<
From an efficiency standpoint they're pretty mediocre... the exhaust hose leaks alot of heat back into the space (just due to being thin and flexible) and unless you make a special port for it or something then you tend to have to have the window open the whole time you're using it.
I've never seen one on 220, and at 110 the absolute best it can be as a heater is a hair dryer (1500W space heater if you prefer). As air conditioners though they really do have their uses. You can easily put out 12k btu and if you've ever had to paint an unconditioned space (where you had to crack a window for ventillation regardless) in the dead of summer you can understand what a nifty tool portable air conditioning can be.
TL;DR I can't imagine using one as a permanent solution, but they aren't a "gimick" and do function as advertised.
Offered only as an opinion,
Michael Lawrence, LISSCO
