GSHP vs ASHP: The Complete Comparison
How They Work
Air source heat pumps (ASHP) extract heat from outside air. Ground source heat pumps (GSHP) extract heat stored in the ground via buried pipes (ground loops or boreholes).
Efficiency
GSHPs are slightly more efficient (COP 3.5–5.0) than ASHPs (COP 2.5–4.5) because ground temperature is more stable than air temperature.
Cost
ASHP installation: £8,000–£15,000. GSHP installation: £15,000–£35,000 (ground loop/borehole adds significant cost). Both eligible for the £7,500 BUS grant.
Space Requirements
ASHPs need space for an external unit (similar to an air conditioning unit). GSHPs need large garden space for ground loops, or a borehole — expensive but space-efficient.
Which Is Right for You?
ASHPs are the right choice for most homes — lower cost, simpler installation, widely available. GSHPs suit rural properties with large land and budgets for the higher installation cost.