Ground-source heat pumps use the ground and/or groundwater as heat source in winter and heat sink in summer. There are several types of access to the ground to extract heat: groundwater wells, horizontal coils, borehole (vertical) heat exchanger, geostructures. Usually ground is coupled with a vapour-compression heat pump, driven by electric power. It is worth to consider, from Thermodynamics, that to fulfil the same heating load, less power is required on the evaporator side of an absorption heat pump than of a compression one. Absorption heat pumps are gaining increased attention as an environmental friendly heating and cooling technology and the recent development of low capacity water-ammonia absorption heat pump, suggests their application for residential space conditioning. The present study investigates energy performance of a ground absorption heat pump in a residential application by means of a transient numerical simulation model (TRNSYS), comparing to a ground coupled compression heat pump and to a traditional system (air heat pump or fossil-fuel boiler for heating and air-chiller for cooling).