The answer to 'types of heat pump' is that there are several main types of heat pumps used in homes: air-source, ground-source (geothermal), and ductless mini-split heat pumps. Air-source heat pumps are the most common, using outdoor air to provide heating and cooling. Ground-source (or geothermal) heat pumps use the stable underground temperature to transfer heat, which is more efficient but requires more installation. Ductless mini-split heat pumps are a type of air-source system that doesn't require ductwork and can heat or cool individual rooms.
All heat pumps work by transferring heat from one place to another, rather than generating heat directly. This makes them an energy-efficient alternative to furnaces, air conditioners, and other heating/cooling systems. The type of heat pump that's best for a home depends on factors like climate, home size, existing ductwork, and budget.