I saw someone talkng about it here many years ago,he even posted images of some people who died in their bed rooms by carcoal poisoning, I even researched this on Google:
https://en.wikipedia.org/wiki/Charcoal-burning_suicideAny of you have an experience or knowledge about this? seems like a fine way to end it since Coal is dirt cheap everywhere, and All you need besides that is a fully closed room and for someone not to find you within a couple hours, It reminds me of the Carbon monoxide poisoning.