Heat pump retrofit planning — every off-gas D–G rental in your patch

BUS is open to homeowners and private landlords across England and Wales, regardless of income, who replace a fossil-fuel heating system with an MCS-certified air-source heat pump, ground-source heat pump, biomass boiler, or air-to-air heat pump system. Grant values: £7,500 ASHP/GSHP, £5,000 biomass, £2,500 air-to-air. The grant is applied for by the installer, not the homeowner, and paid as a discount on the invoice. Eligibility excludes new builds and properties with valid loft/cavity insulation recommendations on their EPC that have not been actioned. The scheme is open through March 2030 with a £400m annual budget for FY26-27. See the official BUS policy note on gov.uk for the full eligibility list.

MCS — Microgeneration Certification Scheme — is the UK quality mark required for any installer whose customer wants to claim the Boiler Upgrade Scheme grant. Without MCS certification, no BUS grant flows through your work, which on a £12,000 ASHP install is £7,500 of customer money you cannot unlock. MCS certifies the firm, not the engineer, and covers heat pumps, solar PV, batteries, biomass and small wind. The public registry at mcscertified.com is searchable by trade and postcode. Around 5,250 contractors hold MCS today across all renewable trades; only around 2,200 are heat-pump certified, which is the bottleneck the Warm Homes Plan needs to break.

Search your postcode plus a radius and EPC Hunt returns the off-gas EPC D-G rentals — usually a few hundred to a few thousand within a 10-mile patch in rural Wales or the South West, fewer in dense gas-grid urban areas. Heat-pump suitability layers on top: rentals with current heating fuel of oil, LPG, solid fuel, coal or biomass score highest because they have no incumbent gas connection to defend. The retrofit-priority score weights these properties up automatically. A typical Welsh or rural English heat-pump installer working a 30-mile patch sees between 1,200 and 8,000 candidates depending on density. Wales over-indexes — household MCS uptake is 8.74%, the UK highest, against an England average of 5.86%.

ASHP — air-source heat pump — extracts heat from outside air using a unit that sits outside the house, looking like a small air-conditioner. Install cost £8,000–£14,000, BUS grant £7,500, footprint a couple of square metres. GSHP — ground-source heat pump — extracts heat from the ground via a buried loop or borehole. Install cost £18,000–£35,000, BUS grant £7,500, requires significant garden or land. ASHP is around 90% of new UK heat-pump installs because the install footprint is smaller, the cost gap is large, and the performance gap closes once outside temperatures sit above 0°C. GSHP shines on rural properties with land and high heat demand. EPC Hunt surfaces both filters, and our retrofit-priority score weights ASHP-suitability higher by default.

Yes. The fuel-type filter accepts mains gas, oil, LPG, solid fuel, electric, biomass and district heating. The off-gas signal — oil, LPG, solid fuel, biomass — is the highest-value cohort for ASHP and GSHP retrofit because the incumbent fuel cost is already two to three times mains-gas pricing, so the heat-pump payback maths is tight. Around 1.7 million UK homes are off-gas; rural Wales, the Scottish Borders and Northumberland over-index. Combine the fuel-type filter with EPC band D-G and a recommended-measures filter for "low-carbon heating" to get the cleanest off-gas heat-pump pipeline. Boiler-replacement candidates — homes with mid-life gas boilers — are filterable too, though their priority scores lag the off-gas cohort by a wide margin.