Ground source heat pump (GSHP) systems can provide cost-effective space heating and cooling for buildings while using less fossil fuel compared to many conventional systems. Despite these benefits, they typically have higher upfront costs and longer payback periods than other heating and cooling systems. These costs are often seen as potential roadblocks for property owners to install GSHP systems over conventional systems. The financial attractiveness of GSHP systems can be increased by adopting a hybrid ground source heat pump (HGSHP) system where GSHP systems provide the baseload thermal energy with the balance provided by conventional systems. This paper assesses the lifetime costs of GSHP and HGSHP systems designed for seven major cities in Australia and compares these costs with the lifetime costs of conventional systems. The results indicate that adopting HGSHP systems in Australian climatic conditions (from tropical to cool temperate) and under current Australian installation and fuel costs can lower the normalised lifetime costs of heating and cooling compared to adopting a GSHP or a conventional system only for the same applications.