A properly burning kerosene heater has insignificant CO in a well ventilated area.  What that means is it didn't make my meter move.

I've not tested one in a closed tight environment like a tent.   There's a reason for that.  Though we typically talk about CO as our major concerns, which being the most deadly it should be, other than simple alcohol which when complete burns gives off C02 and water, these fuels are complex hydrocarbons so give off all sorts of things other than C02 and water.  Assuming your health is fair, they're typically not a problem in well ventilated areas but they do concentrate quite a bit in closed in areas like cars, tents, etc.  I call this other effluent noxious gas for it can make you quite noxious in high concentrations.  

Of course, I've yet to find the Kerosene heater that puts out as much noxious gas as the old Coleman white gas heaters.  Those things, wow, I look back now and am amazed I survived them.  They were like burning three or four Coleman lanterns in your tent.  You'd wake with the headache from hell and foul mouth it took hours to rid.  

Anyway, I haven't tested a kerosene heater in a closed environment.  Its not recommended by the manufacturer and I have no intentions of doing it if anything for the noxious gases not really the CO threat.  

In a home and even as small as a small trailer home, these heaters do just fine that's ran properly.

That ran properly thing can be quite the challenge to some people during long term use.  I find the towers to be far more forgiving.  Any heater that relies on light as a form of its heat, the wick control then becomes very critical to the application and you give up much more wick adjustment.  Over the decades of being around these things, I can't tell you the homes I've been in that used the small area kerosene heaters that on prolonged use, the smell was so strong you'd almost be afraid to light a match.  You really have to stay on top of the wick on those things and eventually in prolong usage its so often, it wears its users down and they live with the fumes rather than fix the wick.  The users also get use to the smell over time so not only don't fix the issue but ignore it.  

The towers on the other hand have far more wick adjustment and a person can actually go a very long time, even seasons, without doing anything to that wick other than adjust that flame height to where its enough to turn that reburner cage hot and the flame burn nice and even.  They are, of course, giving up a little control (on the high end) but these heaters put out so much heat, they can afford to.  

This is why I do not recommend the little area heaters and lean people to the towers instead.  

Yes, there's a thread somewhere I did measuring CO output under various conditions of all sorts of things from propane lights to Coleman heaters.  Most of my testing over the years has been in closed in environments like a car.  It was fun and quite illuminating.  One that jumps out at me is how little a Coleman lantern puts out but then poke a small hole in that delicate mantle and bang, it goes through the roof.  

Anyway, in the last decade or more, I've yet to notice any CO increase in my home from a kerosene tower.

Tj