In the fire industry, BTU stands for British Thermal Unit, which is a measurement of energy. One BTU is roughly equal to 1.06 kilojoules or the amount of energy required to raise the temperature of one pound of water by one degree Fahrenheit.
BTU ratings are used to compare the heat output potential of fire features, such as gas fireplaces, grills, and fire pits. The higher the BTU rating, the greater the heat output, making it an important factor when choosing a fire feature based on heating needs.