This doesn’t produce carbon monoxide?
Better you freeze to death than increase your carbon foot print and cause more Globull warming!
I don't know. I have read that rooms heated with candles become oxygen-depleted, so stick your head out the window every once in awhile and get a breath of fresh air.
No, not much, at least not initially. Most forms of combustion don't produce CO instead of CO2 until the air becomes oxygen-depleted. Which of course causes its own problems for occupants.
CO is nothing to mess about with. A co-worker couple decades ago misused some equipment and wound up with permanent brain damage. Very sad.