If the excess heat is exported for heating of buildings, at a temperature below 150 °C (423,15 kelvin), Ch can alternatively be defined as follows:
I gcás ina ndéantar an teas iomarcach a onnmhairiú do théamh foirgneamh, ag teocht faoi bhun 150 °C (423,15 K), is féidir, mar mhalairt air sin, Ch a shainmhíniú mar a leanas: