Waste heat comes under the umbrella of "unavoidable energy" and is produced as a by-product of any process whose primary purpose is not to generate heat. We use the term waste heat because this energy is often lost.

However, waste heat can also be harnessed and put to good use. This is known as recovered energy and is used in conjunction with renewable energy to meet the goals of the energy transition act, which include curbing CO2 emissions. The idea is to foster a circular economy by recycling a source of heat that has in the past been overlooked.