How a GSHP works
A few metres down, the ground holds a stable temperature all year. A ground source heat pump circulates fluid through buried pipework — horizontal loops in trenches (needing significant land) or vertical boreholes (compact but costly to drill) — and upgrades that heat for space heating and hot water.
Because the ground source doesn’t drop with the air temperature, GSHPs deliver a higher, steadier SCOP (typically 4+) than air source units, with peak efficiency exactly when heating demand peaks.
In the SAP calculation
Everything said for heat pumps generally applies, with a better SCOP: a GSHP is usually the strongest heating entry a SAP calculation can carry, and a robust answer to demanding planning conditions.
When it makes sense
Install cost is the catch — groundworks or drilling put GSHPs well above ASHPs. They earn their premium on larger dwellings with bigger heat demands, plots with available land, projects where the external unit of an ASHP is unwelcome, and multi-dwelling schemes using shared ground loops (increasingly popular, and well-treated in SAP). No outdoor fan unit also means silent operation.
Weighing GSHP vs ASHP for a project? We’ll model both in SAP so the decision is numbers, not guesswork. Ask us.