We had a published article on GreenBuildingElements.com on the inefficiencies of open fireplace use and how home heat can be saved with a Chimney Balloon fireplace damper.
The article will look familiar since we had also posted it on our blog a few weeks ago. Here is a link to the complete article: http://greenbuildingelements.com/2008/09/22/how-to-stop-your-fireplace-from-being-an-energy-eater/