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How Can I Work Out A Gas Fireplaces Output In BTU British Thermal Unit?

June 10, 2012

Gas Fireplaces are increasingly popular and much more convenient and practical than solid fuel appliances that need constant fuel to keep the fire going. Unfortunately the heat output of gas fires is very ambiguous and it is often difficult to compare and contrast fires. We often get asked by our customers to work out the output of gas fireplaces using the conventional term BTU which is very well understood as it is used for radiators and central heating systems. However, it is not as straight forward as it may seem to work out the heat output in a BTU unit a [British Thermal Unit] s the appliances are not quoted in this manner. The heat output of gas fireplaces are often quoted in kilowatts (KW) and both heat input figures and output figures are quoted.


1 kWh = 3412.14 Btu

Fire Efficiency

To understand the how hot the fire gets you must consider the heat output rather than heat input. The difference between how much a fire consumes of gas (heat input) verses the heat output is referred to as the efficiency. Despite how straight forward this may seem, the manufacturers efficiency ratio is different to the ratio heat input divided by output, as companies strive to maximise the advertised efficiency and use other measures to determine this. For this reason (usually the case) if you see a fire advertised at 90% efficiency and consider the given heat input and output, then it will not equate to the 90% efficiency quoted (quite bizarre)