Retrofit cost UK, 2026.
Two quotes on the kitchen table: heat pump on its own, or a phased deep retrofit drawn out across the PAS 2035 measure stratigraphy. The cap, the grants and the process fees are all set out below, line by line, with a source against each end of every range.
Three UK suppliers publish a post-grant price for an air-source heat pump: Octopus £4,064 as its typical figure, E.ON Next from £4,946, Aira £6,729 as a worked example, all after the £7,500 Boiler Upgrade Scheme grant. A phased deep retrofit across fabric, ventilation, heating, renewables and controls under PAS 2035 runs £35,000 to £70,000. What the heat pump will not do is pay for itself out of running costs: at the cap for 1 October to 31 December 2026, a gas boiler at 85% delivers heat at 9.38p per kWh and a heat pump at the national trial median SPF of 2.78 delivers it at 9.47p. The grant is the case, not the fuel bill.
Heat pump only
A 7 to 12 kW ASHP, low-temperature flow design, BUS grant of £7,500 applied at point of installation.
| ASHP supply and install, 7 to 12 kW | £8,000 to £14,000 |
| Radiator upsize for low-temp design | £1,800 to £4,500 |
| Smart heating controls | £350 to £950 |
| Less BUS grant | (£7,500) |
| All-in (post-BUS) | £2,650 to £11,950 |
Phased deep retrofit
PAS 2035 stratigraphy across fabric, ventilation, heating, renewables, controls. Sequenced over five to ten years against the medium-term improvement plan.
- Stratum 1FabricEWI or IWI, loft top-up, suspended-floor insulation, glazing review£14,000 to £30,000
- Stratum 2VentilationMVHR if airtight, otherwise PIV plus trickle review£500 to £11,000
- Stratum 3HeatingASHP plus low-temp radiator upsize and pipework checks£9,800 to £18,500
- Stratum 4RenewablesSolar PV 4 kWp plus 5 kWh battery (where roof and orientation suit)£8,300 to £14,050
- Stratum 5ControlsWeather and load compensation, zoning where worthwhile£350 to £950
Line items in Quote A are gross of grants and the BUS row subtracts from them, so the column adds up as written. The Grant Ladder below subtracts the ECO4 (if eligible) and GBIS (if eligible) layers on top; the 0% VAT relief on energy-saving materials is netted at quote stage by the installer.
| Octopus Energy, Cosy 6, typical (median) post-survey price, quotes 1 Jun to 30 Sep 2026 | £4,064 |
| E.ON Next, Worcester Bosch Compress 2000 AWF, typical 2-bed, from | £4,946 |
| Aira, worked example, 6 kW system | £6,729 |
| Nesta, median install across the Boiler Upgrade Scheme 2025/26, before the grant | £13,041 |
The first three are after the £7,500 grant and are each the supplier's own published figure, not an average of quotes we have seen. The Nesta line is gross: take £7,500 off it and the scheme-wide median lands at £5,541, inside the same band. British Gas, OVO, Heat Geek and the installer networks are survey-first with no published price, which is a legitimate model and not a dodge. See the installer file.
- Boiler Upgrade Scheme£7,500 ASHP / GSHP, £5,000 biomass, £2,500 air-to-airEngland and Wales, owner-occupier or private rented, MCS installerLive
- ECO4Whole-house treatment, indicative £8,000 to £12,000Low-income or health condition, LA Flex routes availableClosing soon
- Great British Insulation SchemeSingle measure, average £1,200 to £1,800 to householdEPC D to G, Council Tax bands A to D in EnglandLive
- 0% VAT on energy-saving materialsSaved at point of installer invoiceEngland, Wales, Scotland and NI to 31 March 2027Live
- Warm Homes Plan + Warm Homes LoanTBC, £5 billion envelope (DESNZ)From early 2027Incoming
Pick the working file you need.
Two-quote comparator
Settle the £8 to £14k versus £35 to £70k question for your archetype.
Grant stackNet-after-grants
BUS, ECO4, GBIS, 0% VAT, in the order Ofgem and DESNZ apply them.
ProcessPAS 2035 line items
Assessor £400 to £800. Coordinator £1,500 to £3,500. Designer and monitoring split out.
Risk path before measure list.
PAS 2035 tiers projects by EPC band and traditional construction. The path determines whether a Retrofit Designer is mandatory and how much survey work the Coordinator carries. The path is set on day one and cannot be unset.