Get Warm or Die!

There has been a modest discussion going on (in Facebook amongst people living in Japan) about the various problems with heating systems in Japan and the general lack of insulation in houses – even in the snowy climes of Japan's back country, Niigata.
To get to the bottom of this issue, Pterosaurish went to the store to look into what modern heating conveniences were on sale this year!
Store Scenario
Salesman: May I help you, sir?
Pt (me): Yes, I am looking for a room heater... what is good this year?
Salesman: Well, because of the nuclear power plant problem and shortage of electricity, we are not recommending electrical air conditioners like we have been over the past 5 years or so.
Pt: What do you recommend instead?
Salesman: Come over here and let me show you. (He leads me to some impressive looking machines) These run on kerosene and are very efficient. You can have the fuel tank put outside your house and ask a kerosene supplier to tank it up for you on a contract basis. You don't need to worry about anything then.
Pt: Wow... they look nice, but the prices! Those cost over 100,000 yen (about $1250)! And that doesn't include the tank for the fuel, does it?
Salesman: (squinting at me as if he has suddenly gotten my "measure") Oh... I see... well, then. Have a look at these. These also run on kerosene, but you have to fill the internal tank yourself. (He pats one of them lovingly)
Pt: Wow... these are only 25,000 yen (about $300). Is the only difference that I would have to refuel it myself?
Salesman: Oh no. Those over there are what we call "clean heaters" while these we call "fan heaters".
Pt: That's a big difference.
Salesman: Ha! Ha! You are SO funny.
Let me explain how they are different. (He begins explaining as if talking to a 4-year old) The clean heaters need to be installed in one position, while the fan heaters can be placed anywhere in the room.
Pt: Hmm... sounds like the fan heater would be more practical. Why is it so much cheaper?
Salesman: Well, one reason is that the clean heaters need to be installed.
Pt: What do you mean?
Salesman: Well... a hole needs to be drilled in the wall for the air and exhaust duct to extend outside. It draws its combustion air through this pipe and also passes exhaust gases outside. That's why it's called a "clean heater".
Pt: (getting a bad feeling) Then what about the air and exhaust of the fan heaters?
Salesman: The fan heaters draw their combustion air from the room and vent exhaust into the living space as well.
Pt: You mean they pump carbon monoxide and carbon dioxide etc. directly into the room?!
Salesman: (laughing) Ha ha ha! I can see by your face that you are concerned. There is no need to worry! Each fan heater comes with a prominent sticker on top, explaining that you need to open the windows to ventilate once or twice an hour.
Pt: Let me get this straight... the fan heater pumps exhaust gases into the room as it heats the living space....
Salesman: (cheerfully) Correct!
Pt: And then just as the room is warming up, you are supposed to go and open a window to ventilate out the dangerous gases....
Salesman: (even more cheerfully) Yes! That's how it works!
Pt: So.. like... what if you fall asleep (or are overcome by poisonous fumes) because it is SO warm and cozy with the new heater..
Salesman: . . . . . . .
Pt: ...and what if you don't open the windows and let all the heat out?
Salesman: Well... as this other sticker on the back warns, you could be overcome by the gases.
Pt: And what...?
Salesman: (not so cheerfully) And ... well... die.
Pt: Do you sell these on credit?
Salesman: (cheerfully again) Of course! We accept all major credit cards! Do you want to buy this one now?
Pt: No, I was just wondering if these were a good credit risk. Thank you for your help.
Salesman: No problem! Please come back again when you decide which one to buy!