Geothermal energy is estimated to currently supply 19,429 billion Btu/yr (20,478 TJ/yr - 5,689 GWh) of heat energy through direct heat applications in the United States. The corresponding installed capacity is estimated at 5,373 MWt. Of these values, direct-use is 8,044 billion Btu/yr (8,478 TJ/yr - 2,355 GWh) and 573 MWt and geothermal heat pumps the remainder. It should be noted that values for the capacity and the energy supplied by geothermal heat pumps are only approximate since it is difficult to determine the exact number of units installed and most are sized for the cooling load, thus they are oversized in terms of capacity for the heating load (except possibly in the northern U.S.)