Possibly *[Old Black Witch](https://forgottenstoriesweb.wordpress.com/2017/10/04/old-black-witch/)* by Wende and Harry Devlin, as per [this answer about the TV adaptation](https://scifi.stackexchange.com/questions/253389/short-film-about-a-woman-solo-parenting-a-boy-who-move-into-a-house-with-a-witch/253394#253394).

[![Front cover of *Old Black Witch*][1]][1]
> A boy called Nicky and his mother are looking for a new place to live somewhere in New England.  The mother wants to buy an old cottage with the idea of turning it into a tea room.  At first, they have trouble finding a place, but finally they buy an old house that badly needs fixing up, not knowing that there is an old witch living there.
> 
> The witch (whom they call Old Black Witch, since she’s dressed all in black and sooty and doesn’t seem to have any other name) has been sleeping in the chimney of the house for about a hundred years, and they wake her the first time they try to start a fire in the fireplace.


  [1]: https://i.sstatic.net/9ktrEm.png