I've got a small portable heater purchased from Target for about $10.

When you first turn it on, it always has that burning smell from the element heating up.
It clears up after about 10 min.

Recently, I turned it on in a room with a CO detector, and that smell set it off.
What's the correlation? There's no oil or anything to give off CO? Is it still safe? Should I just open the windows while it's warming up?

EDIT: It's electric. Detector is new and it sets off as the heater is turned on.
Is it really emitting CO or is the defect just setting off a false positive on the detector?

  • 2
    Is the heater gas or electric?
    – longneck
    Nov 27 '13 at 15:16
  • 2
    A $10 portable propane heater is an outdoors use only unit. You're going to pay more for something that's certified safe for indoor use. A $10 electric heater that's smoking off industrial contaminants such that it stinks is highly suspect as to what it's contaminated with, shouldn't be setting off a CO detector. You've got a weird one. Dec 10 '13 at 17:39
  • Now that we know it's electric, is it ceramic block, ni-chrome coil or one of those really cheap oil-filled heaters with a lot of paint surface area that wasn't properly baked at the factory? Dec 10 '13 at 17:51
  • 1
    Is it a combination CO\smoke detector?
    – Mazura
    Oct 31 '14 at 0:22
  • yes, it is a combo
    – eych
    Nov 3 '14 at 18:41

If your carbon monoxide alarm is going off, you need to assume that there's actually carbon monoxide in dangerous levels in that area. If the heater is electric it probably shouldn't be emitting CO but maybe there's a manufacturing defect that's causing the heating element or plastic to burn.

CO is lethal and totally undetectable by people, so if the alarm goes off you need to leave the building and open the windows. The absence of smoke does not mean that you are safe.

(CO detectors have a limited lifespan: 2-10 years, depending on the model. There should be a date stamped on it somewhere. If it's at "retirement" age you should probably replace it anyway, and then you can see if the new one still goes off.)

Revision based on question update:

You must not ignore the CO detector. People can and do die in their own homes of CO poisoning, oblivious to the problem. Unlike smoke/fire, there's no way for you to tell the source of the problem or evaluate its severity, and no way to tell if the problem has been resolved. You probably have a sub-standard or defective heater — I would not use it anymore.

  • Until the catalyst block heats up to glowing red, propane heaters will give off CO. Also if your propane is oil contaminated (they make filters for this), the catalyst block can fail to do a complete, clean burn. Not something to mess with, always buy certified room safe AUXILIARY heating equipment if you're going to run it indoors, have two CO detectors and DO NOT RUN IT WHILE ASLEEP. Dec 10 '13 at 17:35
  • Above is a general warning, question was edited to clarify it's some electric unit offgassing on startup. Dec 10 '13 at 17:41

Don't mess with CO. I'd buy a new CO detector and test it out with the heater if it happens again return the heater and alert the company. It could be a defect they need to be aware of. Good luck

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