Not quite on topic, but...

I have a conventional woodburner which has been made far more effective by the recent addition of an old 12v 4 inch computer fan. The fan sits at the rear of the woodburner and is playing on it. It helps circulate warm air around the room.

Have a look at a UK website called something like: 'Its not easy being green'. There's an interesting section devoted to wood as a heat source.

JJ