That is kind of a loaded question. The wood stove should put out more heat FASTER, the coal more heat LONGER. if it is 40 out and you want heat fast= wood, if it is 4 out and you want to be warm all day= coal. The wood stove will come up to temperature faster and will almost certainly get hotter, but will have to be fed every couple of hours, the coal will come up more slowly but only has to be fed every 10 hours or so. If you are home all day and can tend the fire whenever it is needed it probably doesn't make a lot of difference because either will put out as much heat as you want, however if you are going to be out all day (at work or whatever) you can't stuff enough BTUs into the wood stove to last all day, with the coal you can. In that case the coal wins out hands down.