At Mamaw's she had a small fireplace that had two grates to burn in,one in the main room and one on the other side in a bedroom.Voal was cheap or free.

As coal trucks drove past the house lumps of c oil would fall off and we picked them up to burn.
Sidenote:a few truck drivers were young and I'd stand on the porch and flirt with one in particular.

As a preteen the house we lived in had a coal furnace in the basement and vents were located through the house.We had to order coal to be dumped outside by a shute to the furnace.Other places after that were natural gas.