Heating a house....

When my house was built, the fireplaces have "sleeves" around them and vents at the bottom of the fireplace and one or two at the top. As the fire heats up the inner part radiates heat into the sleeve and it comes out of the top vents.

We would put some fans in front of the bottom vent(s) and then get better circulation and more heat out of the top vent. One year we threw a New Year's party and I had that sucker putting out so much heat (I like BIG fires) that people were holding the door to the outside open to cool down - in middle of winter in Chicago!!!

If you put a jacket/sleeve around the heat source and then push the air with a cheap fan, it can put out alot of heat.