Miracle Heat Blower Fan for Wood Stoves. The US Stove Miracle Heat Blower is compatible with wood or coal stoves and furnaces and is designed to improve the efficiency of an older stove or furnace. This blower features an integrated thermo disk that senses the heat in the chimney and once hot, blows air through the heat exchanger to bring up to an extra 10% of the heat loss back into the room. Easy to install into a 12 in. Section of the stove pipe just above your stove, this blower is ultra-quiet and has fully automatic operation. Constructed from steel for long-lasting durability and reliability. Blows air through the heat exchanger and brings up to 10% of the heat loss back into the room. Automatic operation for ease-of-use. Fully sealed from flue gases. Easily installs into a 12 in. Section of the stove pipe just above the stove. For use with wood or coal stoves or furnaces. Designed for 6 in.