Heat source habitable rooms

The house I inspected has had the garage converted into habitable living space, with no other heat source other than a fireplace. My question, Is a fireplace considered a heat source for habitable rooms? And if not, is there a reference?Thanks,

I don’t think a fireplace has been a heat source for a few decades or so. However, I could be wrong. If one uses common sense here, the damper should be open when there is a fire, so since heat rises, much of the heat will go up the chimney.

Back when fireplaces were heat sources, there were fireplaces in every room, and the fireplace took up a whole wall; one could almost stand upright in some of them.

Fireplaces now are for Valentine’s Day, anniversaries, birthdays, etc., not as a main heat source.

Sounds like a perfect location for a wood/pellot stove.