Supplying 10% of GB home heat (≈23.7 TWh/yr): CHRS vs ASHP vs GSHP

 

Common target so you can compare like-for-like: ~2.07 million homes’ heat per year.

                                                                                                                                                                                                                                   

Option	Units to hit 23.7 TWh/yr	Electricity needed	Typical COP	Deployment realities
CHRS (800 m stacks feeding district loop)	≈ 16,500 stacks (1.44 GWh/yr each)	≈ 7.2 TWh/yr (23.7 ÷ 3.3)	~3.3 (stable, shallow clay source)	Invisible; trenchless HDD; centralised plant; HIU in homes; land remains usable; modular ring mains with spurs to estates, villages, cottages.
ASHP (individual homes)	≈ 2.07 million units (1 per home)	≈ 9.5 TWh/yr (23.7 ÷ 2.5)	~2.5 (drops in cold, defrost cycles)	Outdoor units on façades/gardens; noise; visible; grid peaks in cold snaps; millions of installs/servicing visits.
GSHP (individual homes)	≈ 2.07 million systems (unless built as larger plants)	≈ 6.2 TWh/yr (23.7 ÷ 3.8)	~3.5–4.0 (good, but site-dependent)	Deep boreholes or large trench fields per plot; high capex per home; land take; slower to retrofit at scale.

 

    Assumptions: Mean home heat ≈ 11,451 kWh/yr; CHRS 800 m stack ≈ 1.44 GWh/yr delivered (@COP≈3.3); illustrative seasonal COPs: ASHP≈2.5, GSHP≈3.8.     Electricity figures are annual energy, not instantaneous peak power. CHRS figure represents central plant draw, typically flatter across seasons.