Our high efficiency inset gas fires are a direct replacement for any existing inset gas fire installation or they can be supplied as a complete package with surround and hearth for a new installation. These fires are tested to BS7977:2013, the latest Standard for safety and efficiency. The fires can be used in any existing chimney – Class1, Class2 or Pre-Cast or can be installed using a flue box and flue liner and a false chimney breast in a new build property. By replacing an old inset fire with a CVO high efficiency inset gas fire you could benefit from up to 60% more heat in the room for 50% of the cost. Tested to BS7977:2013 Standard : Class 1 Energy Efficiency Rating EFFICIENCY RATINGS: When comparing appliances tested to the old 2001 standard you should consider that these older fires can have actual efficiency ratings up to 25% less than the quoted figures when compared to a new fire tested to BS7977:2013. For instance an old 2001 inset gas fire quoting 85% efficiency will probably be only 63% when tested to the new 2013 standard.