The principle behind these things is a double burn, much like the catalytic converter in your car works.  That cage around the wick needs to get hot enough to do a second burn, a dull red.  With a proper burn, you have almost no CO and for that matter smell.  

What that means is the burn needs to be nice and even with no flicker.  That soot build up, btw worse than my stove I had ten years I gave away, means the previous owner was probably burning his too high or too low and not getting a proper burn.  An improper burn is going to char the wick in places and it may need trimmed and height adjusted, may not.  If he didn't let it burn out, then the wick may be gummed, which you can clean with fresh kerosene. You'll only find out by firing it up and seeing.

On a tower heater, there should be a small amount of adjustment. You adjust for a proper burn which in a new properly working one means you can adjust the heat level some.  The more gummed and charred, the less control over you have over the heat level as you try only for a proper smooth burn.  Can't achieve a smooth burn, no flicker, time to pull some maintenance on the wick.  

I use mine every winter to augment my heat pump to limit the strip heat once the temps get below 20 degrees.  My last two heaters, I bought spare wicks and never had to use them.  I didn't even bother this new one I have now.  What I'm saying here, use these things right, that wick last a very long time.  Its no different than a kerosene lantern.  You adjust the wick so you get a nice even burn, no smell and no soot.  

Obviously if you follow this then when you first fire one up, every time you fire it up, you are going to get kerosene smell.   That cage/reburner needs to be hot.  What I do is light mine outdoors, let it heat up, then carefully move it indoors using the two handles.  The cage will heat up before those handles do.  Once its lit, I fill it burning by watching the level gauge keeping in mind some will go in after you vent the syphon tube.  In other words, only fill it till the needle hits full, not over fill.  Keep a rag handy just in case.  The pan on the bottom will catch a little over spill but once you get the hang of it, you won't have any.  Keep that thing burning if you can until you are done with it.  When done, let it burn out.  

Once you use these things, you get use to doing a little wick maintenance once a year.  That's not hard to deal with.  

I use kerosene here from the pump which is good quality but that varies area to area.  I keep 20 gallons around which gets me about five days used frugally.  I put mine in the lowest level of my house, centrally located then control heat to each room by using the door and how open or closed it is.  That's a bit of a learning curve but I can heat a 3,000 sq/ft house that way some rooms nice and comfortable while others colder.  It really is a lot like using an old pot belly stove that way. Of course, the temperature changes a lot, you have to make some adjustments to your door vent plan.   It doesn't take long to get into a routine of not just how to use your doors, but when to fill the tank.  

A little pot belly stove trick is if you don't have a door, hang sheets.  That will let limited heat through but will divert most of the heat.  

Tj

I'm a bit surprised that no one has mentioned the GURU of Kero devices, Miles Stair:http://www.milesstair.com/.

Go to his site, and read up.  Everything you need to know, and lots more.  He's GTG, and his wicks are second to none.

I've been a customer a number of times.

Disclaimer: no financial interest.

Just to be safe, I would suggest installing CO detectors anywhere near where these things will be used.  If your existing smoke detectors are getting on in years (they should have a replace date on them, or at least a manufacture date), replace them with combo units.  I used my Kero heaters for 3 days last year when the power went off, and the CO detectors didn't make a peep.  Well-sealed house, too.  However, better safe than sorry.