If you read the instructions accompanying this heater you will find that it warns you to have adequate ventilation when you're using it.  Combustion of any carbohydrate fuel produces CO, which can be nasty.

Dave in KC
http://members.fortunecity.com/davebaker1/westy/westy.htm

  ----- Original Message ----- 
  From: Schmidt 
  To: vanagon@GERRY.VANAGON.COM 
  Sent: Friday, December 22, 2000 9:16 AM
  Subject: lifesaver heater

  Last winter I bought a little coleman heater that is fueled by the little bottles of propane(the screw on kind.
  While it does not put out enough heat to heat the cavernous interior of the westy, it is great for warming body parts.  A rule of cold weather camping states that if your feet are cold when you get in your bag, they will remain cold.  This heater is perfect for heating your pigs so they stay toasty in your bag.  The instructions say this heater can be used IN a tent ie no fumes.  I have always distrusted this and never run it while sleeping in the westy.  Tents are more breathable than(most) top-down westies anyway. 
  In the last week, this heater has saved me twice. Last night it kept the temp tolerable when it was -5 out and I broke down. 
  3 days ago, my gsa cap was froze. Key would not insert.  Station had no "unfreeze" solution.  Not enough in the tank to drive on home.  The heater saved the day-used it outside in this case.  Well worth the
  ...still $45 at Walmart.

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