I've been burning both coal and wood for the past couple of years. My wife likes wood for those days when it's cold, but not below about 30degF. During the day it usually warms up enough because of our southern exposure that she's happy with the heat output of wood. However, when the temps drop below 20 and stay that way, coal is the only way to go. It heats long and even, and depending on what kind of coal I use (nut vs stove) I can get burn times of 18 hours. I like wood for the ease of disposing of ash; coal for the long and high heat value.