Myth #9 - Un-vented gas heaters are NOT safe to operate indoors.  (Wrong!)

The very first two or three paragraphs of every owner's manual of every gas-fired, non-vented space heater cautions the user to operate the heater in a well ventilated space.

In other words, open a window.

Opening a window might be counter productive if you're trying desperately to heat a room in the middle of a cold winter, but facts are facts.

If you use your gas-fired, non-vented space heater in a confined area for an extended period of time, you may die!

Because of all the inconvenient law suits from families who lost people because they couldn't or didn't read directions, the manufacturers of gas-fired (non-vented) space heaters came up with a solution.  They started making their heaters with "oxygen depletion sensors". 

The O2 (oxygen) sensor is supposed to shut off the heater if the oxygen level in the area dropped too low. 

This would be a great solution except for a few things rumbling in the back of my mind. 

First, when a switch or device fails, it usually fails or sticks in its current position.  In the case of an "oxygen depletion sensor", if it sticks, it will probably stick closed, and the heater will continue to run.

Second, when it comes to manufacturing, businesses usually seek the lowest cost for their raw material.  So, in essence, the people making the oxygen sensor are the lowest bidders for that product.

Third, read the warnings on the first few pages of the owner's manual.  (Every heater manufacturer includes them in one form or another.)  The key phrases to remember are "use with adequate ventilation" and "do not use in a confined space" (or something similar.)

In my opinion, using a non-vented space heater with closed windows (with or without an oxygen sensor) while you sleep is like asking to meet the Angels.  You might want to take up parachute jumping or high-wire walking, it's safer. 

If you have an unvented, gas-fired space heater ... open a window.

Get the full story from "Carbon Monoxide Myths".