i know where to set the feed rate/blower for a given ave outdoor temp of 20-35 deg to keep the house ~68deg and only have to adjust it for cold snaps in the zero to minus 10/20 range
but there is a an add on thermostat unit i can get to fine tune it to stay at a given temp but it usually only varies from 65-70 so long as the ambient outside temp stays relatively constant 20-35
So any fuel source for the fire would work the same. Not a function of the coal but the lack of a thermostat and air duct system.