[link|http://www.hometips.com/help/wat2.html|from hometips]
A 1991 study by the Department of Energy (DOE) rated residential energy sources by the average dollar cost per million Btus of heat they produce. Natural gas was found to be $6.05; heating oil $9.30; propane $9.74; and electricity a whopping $24.15. Obviously, these amounts vary with local energy prices and do change over time