High-efficiency and ultra-efficient geothermal or ground-source heat pumps save money by taking heat out of the ground to heat your home in the winter. In summer the cycle is reversed; they pull heat out of your home and discharge it to the ground to cool your home. Ground-source heat pumps use fluid that is carried through flexible pipes that are buried deep in the ground to transfer heat to or from the soil. The systems typically tie into a house’s duct system to deliver warm or cool air throughout the house.