How efficient are open fires and fuel-effect fires?
Open fires are wasteful of energy. An open fire has an efficiency of only about 15 to 30%, meaning that 70 to 85% of the energy content of the fuel goes up the chimney. This is true both for solid fuel fires and for many fuel effect gas fires.
By comparison, efficient heating systems have efficiencies of 70 to 90%. These systems are better value for money than open fires or fuel-effect fires.