The answer to 'types of heat pump' is that there are several main types of heat pumps used in homes: air-source, ground-source, and ductless mini-split heat pumps. Air-source heat pumps transfer heat between the home and the outside air, while ground-source (or geothermal) heat pumps use the stable underground temperature to heat and cool. Ductless mini-split heat pumps are a type of air-source system that doesn't require ductwork.
Each type of heat pump has its own advantages and disadvantages in terms of efficiency, installation complexity, and cost. The best type for a particular home depends on factors like climate, available space, and budget. Consulting with a professional HVAC technician is recommended to determine the most suitable heat pump system.