01 September 1992

Although some engine-driven heat pumps burn gas or oil directly, the majority of heat pumps used for air-conditioning and heating use electrical energy. Their operation does not give rise to CO2 emissions beyond those already produced in the electricity generation process. Furthermore, by converting low grade heat to a higher grade heat, such units can make use not only of natural heat sources, but also of the waste heat which results from many fossil-fuel burning operations. This increases the efficiency of existing fuel use, thereby reducing specific CO2 emissions.
Heat pumps do, however, require a working fluid. Many of the fluids currently in use are chlorofluorocarbons (CFCs), substances now held to contribute to the depletion of the Earth’s ozone layer and to the greenhouse effect. Loss of this fluid during or at the end of a heat pump’s working life can therefore counteract, at least in part, any reduction in specific CO2 emissions that has been achieved. The main objective of this report is to clarify, at the international level, the extent to which heat pumps can contribute to a reduction in the rate of global warming increase.

The report is based on 46 studies from a number of IEA countries and international organizations. Most of these studies examine in detail the relationship between heat pump deployment and the emission of greenhouse gases. A few examine the relationship between heat pump deployment and electricity or fossil fuel energy savings. Two studies examine alternative technologies.