retrofitcost.co.ukA surveyor's working file. Q3 2026 Ofgem cap applied.
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Working file C3

Grant stack: BUS + ECO4 + GBIS + 0% VAT (UK 2026)

How the four live UK retrofit grants stack on the same project in 2026, in the order Ofgem and DESNZ apply them. ECO4 closes 31 December 2026.

Grant stack ladder
  1. Boiler Upgrade Scheme£7,500 ASHP / GSHP, £5,000 biomassOwner-occupier or private rented, valid EPCLive
  2. ECO4 (closing 31 Dec 2026)Whole-house treatment, £8k to £12k indicativeLow-income, health condition, LA Flex routesClosing soon
  3. Great British Insulation SchemeSingle measure, £1.2k to £1.8k typicalEPC D-G, Council Tax bands A-D in EnglandLive
  4. 0% VAT on energy-saving materialsSaved on installer invoiceUK-wide to 31 March 2027Live
  5. Warm Homes Plan + Warm Homes LoanTBC, £5bn envelopeEarly 2027Incoming

Stacking rules

BUS and ECO4 do not double-count toward the same measure but can sit on the same project (heating versus fabric). GBIS is a single-measure scheme and is mutually exclusive with ECO4 for the measure in question. 0% VAT applies at invoice on top of any grant. The Warm Homes Plan and Warm Homes Loan picks up after ECO4 sunsets; sequence works planned for early 2027 around that handover.

Surveyed 22 June 2026. Ofgem Q3 2026 cap applied (gas 7.33p, elec 26.11p, gas standing 29.04p). Next scheduled review 26 September 2026 (Q4 cap publication). [ref C3]
By Oliver Wakefield-Smith, Founder, Digital Signet. Corrections to oliver at digitalsignet dot com.