In misc.consumers.house Al Bundy wrote:
Those unvented heaters stink, literally. It will often smell like you
are using a kerosene heater. That smell is unburned gasses. They may be
legal and meet some standard somewhere, but they are bad news for your
health. Your family will suffer headeaches and breathing problems at
the least. It just ain't worth the headache!

You don't have a gas stove, do you?