Upfront cost reality in London 2026: a like-for-like gas combi replacement runs £2,500–£4,000 installed (Worcester Bosch Greenstar 8000, Vaillant ecoTEC plus, Viessmann Vitodens 100-W); a comparable air-source heat pump install runs £11,995–£17,995 before the BUS grant, around £4,500–£10,500 after the £7,500 grant. The honest gap on cash-out-of-pocket day-one is £2,000–£8,000 — heat pumps are not yet cheaper to install, and the marketing claims that say otherwise gloss over the radiator upsizing, the cylinder retrofit and the typical London siting complexity.
Running cost depends almost entirely on the electricity tariff. On a flat-rate 28p/kWh tariff a heat pump with COP 3.0 runs at roughly 9.3p per kWh of heat delivered — slightly more expensive than gas at 7p/kWh after April 2026 price cap. On Octopus Cosy (12p/kWh in the cheap windows, 38p/kWh at peak) a well-controlled heat pump that pre-heats the building during cheap windows runs at an effective 5–7p per kWh of heat delivered — 10–20% cheaper than gas. Without smart tariff use the heat pump rarely wins on running cost; with smart tariff use it wins comfortably. That is the single most important nuance the industry tends to flatten.
System suitability is the other gating factor. A well-insulated 1930s semi with cavity-wall insulation, loft to 270mm, modern double-glazing and oversized radiators is an excellent heat pump candidate — COP 3.0+ realistic, payback 10–12 years on Cosy. A Victorian solid-wall terrace with single-glazed sash windows, no loft insulation and 1980s radiators is a poor candidate today — COP 2.2–2.5 realistic, running cost worse than gas. The Future Homes Standard from 2027 makes heat pumps the default in new build; existing-stock retrofit is property-by-property. We do not push heat pumps where the property isn\'t ready; we propose the staged path (insulation, glazing, smart tariff first; heat pump 2–3 years later).
Why Electrician London
Honest suitability assessment
We do not push heat pumps where the building fabric isn't ready. Where gas is the right answer today, we say so — and propose the path to heat pump readiness.
Full cost comparison spreadsheet
Side-by-side: upfront, annual running cost on three tariff scenarios (flat-rate, Cosy, Cosy + solar), maintenance, 15-year total cost of ownership.
EPC point gain estimate
Heat pump typically adds 4–8 EPC points; combined with solar and battery the band shift can be 1–2 grades. Material for landlord MEES 2030 planning.
Staged transition planning
If you're not ready in 2026 — fabric upgrades first, smart tariff first, heat pump in 2028–2029 — we plan the staged path with you. Long-term thinking over a single quote.
Cost comparison services
Educational survey work — the actual heat pump install is priced separately on our heat pump electrical and heat pump cost pages.
Heat pump suitability survey
Fabric assessment, radiator sizing review, electrical headroom check, COP estimate
£225
BS EN 12831 heat loss calculation
Room-by-room heat-loss calc — required for any serious heat pump quote
£325
Full system design and quote
Heat pump sizing, emitter scope, control strategy, BUS paperwork
Free with install
Hybrid heat pump + boiler install
For properties where pure heat pump isn't yet viable — note: no BUS grant on hybrids
From £14,995
What we assess on a suitability survey
- Wall, loft and floor insulation level
- Window and door thermal performance
- Existing radiator sizing room by room
- Hot water demand and cylinder space
- Outdoor unit siting options
- Electricity tariff and EV/solar interactions
- Supply size and three-phase consideration
- EPC current rating and post-install projection
- Listed building / Article 4 / conservation flags
- Insurance and mortgage lender implications
Frequently asked questions
Which is cheaper to run in London 2026 — heat pump or gas?
Gas, narrowly, on a flat-rate electricity tariff. Heat pump, comfortably, on Octopus Cosy or Eon Next Drive with the building pre-heated during cheap windows. The "heat pump is always cheaper" claim and the "heat pump is always more expensive" claim are both wrong — the answer hinges on tariff choice and building thermal mass. We model both scenarios for your property on survey.
When does a heat pump not make sense?
Four typical reject cases. (1) Solid-wall un-insulated Victorian terrace with single-glazed sash windows — fabric upgrades first, heat pump in 2-3 years. (2) No suitable outdoor space — front-only Georgian properties in conservation areas. (3) Listed building where consent for the outdoor unit is materially uncertain. (4) Households not on time-of-use tariffs and unwilling to switch — the running-cost case collapses without Cosy or equivalent. In all four cases we say so honestly.
Are hybrid heat pump + boiler systems a sensible middle path?
Sometimes. A hybrid uses the heat pump for the bulk of the year (mild weather, hot water) and switches to the boiler during the coldest 5-10 days when the heat pump's COP drops. Net: most of the carbon benefit, much of the running-cost benefit, and the boiler safety net. Downside: no BUS grant (DESNZ excludes hybrids), and you're maintaining two heating systems. Sensible for borderline-suitable properties; over-engineered for clear-cut cases.
When will gas boilers be banned?
There is no ban as of mid-2026. The previous government's 2025 new-build gas-boiler ban was scrapped in 2023; the Future Homes Standard from 2027 effectively makes heat pumps default in new build via fabric efficiency requirements. Existing properties: no fixed end date, but the direction of travel is clear — 2035 is widely cited as the likely end-of-sale for new gas boilers, with no compulsion to replace working systems. Buy a gas boiler today and it will run for its 12-15 year design life.
How does the Future Homes Standard 2027 affect resale value?
From 2027 most new-build London homes will be heat pump or zero-carbon-ready by default. The second-hand market starts to price gas-only properties as "needs upgrade" rather than "comparable" by the early 2030s. For a property you intend to sell after 2030, installing a heat pump now (with the £7,500 BUS grant and 0% VAT before May 2027) is materially cheaper than the buyer's likely renegotiation discount in 2032.
How do mortgage lenders view heat pumps?
Increasingly positively. Most green-mortgage products (Halifax, NatWest, Barclays, Nationwide) now offer 0.1-0.3 percentage point rate reductions for EPC band B or above — a heat pump typically lifts a band D to band C, and band C + solar to band B. On a £400,000 mortgage that's £400-£1,200/year of interest saving — material to the total-cost picture.
What COP should I realistically expect in a London Victorian terrace?
Seasonal Coefficient of Performance (SCOP) in a solid-wall Victorian terrace with internal-wall insulation, double glazing and oversized radiators: 2.7-3.0 typical. Same building uninsulated: 2.2-2.5. Same building with full retrofit (external-wall insulation, triple-glazed, UFH): 3.4-3.8. The fabric retrofit work moves the running-cost case from "marginal" to "compelling". We do not install heat pumps below SCOP 2.5 forecast.
Does insurance cover heat pump systems differently?
Most building insurers (Aviva, Direct Line, AXA, Admiral) cover heat pumps under standard fixtures-and-fittings perils with no premium uplift, provided the install is MCS-certified. A handful of older policies still treat heat pumps as "non-standard" and ask for a small premium — switching insurer at next renewal resolves it cleanly. We provide the MCS commissioning certificate for your insurer file.
Repair access and parts availability?
For mainstream brands (Daikin, Mitsubishi, Vaillant, Samsung) parts availability is excellent — local distributor stock for common parts (PCBs, fans, expansion valves) and 48-hour delivery on rarer parts. Gas Safe registered engineers are now joined by HPA (Heat Pump Association) registered installers for ongoing service. Annual service contracts run £125-£200/year — comparable to gas boiler servicing.
Listed building or conservation area — gas usually wins?
Often yes, today. The outdoor unit visibility problem and the listed-building consent friction make heat pumps materially harder in listed and Article 4 stock. There are workable patterns — hidden side-return placement, garden-end units with screened bunds — but they're site-specific and slower to consent. For listed buildings we tend to recommend a modern condensing boiler now and revisit heat pumps in 2030 when planning policy is likely to have moved.
How do I plan the staged transition if I'm not ready in 2026?
Three-step path. (1) Fabric: cavity wall insulation, loft to 270mm, replace single-glazed windows over the next 1-2 years. (2) Tariff and emitters: move to Octopus Cosy when ready, upsize the worst-performing 4-6 radiators when they next need replacement anyway. (3) Heat pump install in year 3 when the building fabric is ready and the BUS grant + 0% VAT picture is clearer post-May-2027. The staged path costs £8,000-£15,000 over 3 years but lands a much better SCOP than a 2026 retrofit on un-improved fabric.
Does solar PV change the heat pump vs gas maths?
Yes, materially. Solar PV self-consumption directly powers the heat pump in shoulder season (March-October), reducing the import-electricity component of the running cost. A 4 kWp London solar array generating 3,500 kWh/year, paired with a 6 kW heat pump using 3,000-4,500 kWh/year for heating and hot water, self-consumes 1,500-2,000 kWh of the solar generation against the heat pump load — roughly £400-£550/year of avoided import. The combination flips most borderline cases firmly in favour of heat pump.
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