We heated a 1900 sq ft farmhouse this winter on coal. It cost us about 180 to 200 a month. Only problem was getting the heat to the back bedrooms. We have Harmon coal insert in the fireplace. We figure it saved us 200 a month at the very least over burning the fuel oil.
I use those little fans that mount in the upper corner of the door frame,They work great in this 1776 farm house.