Calorie

A calorie is a formerly common unit of measure for heat, with the abbreviation ‘cal’. 1 cal is the amount of heat required, at normal pressure, to increase the temperature of 1 g of water from 14.5 °C to 15.5 °C. 1,000 cal = 1 kcal. In the international system of weights and measures, the calorie has been replaced by the Joule. 1 cal = 4.1868 J (old conversion ratio, 1 kWh = 860 kcal for cooling system calculations).