Claim: “Heat pumps are a bad solution economically and environmentally”

Accuracy Assessment: ✅ Largely True

The core economic argument holds up to scrutiny: when the goal is maximising CO₂ reduction per pound of public money spent, heat pump subsidies are among the least cost-effective interventions available. Independent analyses from the UK government’s own advisers, energy economists, and the National Audit Office converge on the finding that the cost per tonne of CO₂ abated through heat pump grants substantially exceeds that of supply-side renewables such as onshore wind. Current UK Boiler Upgrade Scheme (BUS) grants of £7,500 per installation imply an abatement cost in the range of £200–500/tonne CO₂ — far above the EU Emissions Trading System carbon price (~£50–70/tonne) and several times the cost of equivalent CO₂ reduction from new onshore wind (~£30–80/tonne at marginal cost). Serial nuclear programmes such as those executed in France, Japan and South Korea achieve LCOE figures of $61–120/MWh, implying CO₂ abatement costs of £50–150/tonne — materially below the BUS per-tonne cost.

The environmental picture is more nuanced. Heat pumps do work — a modern air-source heat pump (ASHP) with a Coefficient of Performance (COP) of 3 to 4 already produces significantly lower lifecycle carbon emissions than a gas boiler, even on the current UK grid (roughly 150–180g CO₂/kWh as of 2023–24). The technology is sound and the carbon arithmetic is favourable today — but the subsidy strategy is questionable. Investing the same money in decarbonising electricity supply would both reduce the carbon intensity of the grid further and make any future heat pump rollout automatically cleaner and more cost-effective. The sequencing argument — clean the grid first, then electrify heat — has genuine merit that mainstream policy discussions often underplay.

The solar analogy is substantially accurate. The UK’s Feed-in Tariff scheme for residential solar was widely condemned as regressive and wasteful because it paid far above market rates for small-scale generation, transferring wealth from all billpayers to capital-owning homeowners. The BUS replicates some of those structural flaws: it is available only to households wealthy enough to afford the residual installation cost, and its cost-per-tonne-of-CO₂ is unjustifiably high relative to alternative decarbonisation options.

Key Claims at a Glance

Claim Breakdown

1. Heat pumps are a relatively expensive way to reduce CO₂ compared to supply-side investments

✅ Largely True — Subsidy-based CO₂ abatement from heat pumps costs £200–500/tonne; wind costs £30–80/tonne

The Boiler Upgrade Scheme (BUS), launched in 2022, offers a £7,500 grant toward the installation of a heat pump. A typical air-source heat pump installation in the UK costs £10,000–£15,000 all-in; the grant covers roughly half of this. The CO₂ savings from replacing a gas boiler with a heat pump depend on:

1. The heat pump’s Coefficient of Performance (COP) — typically 2.5–3.5 for installed UK systems (seasonal SPF)
2. The carbon intensity of the UK electricity grid — approximately 150–200g CO₂/kWh in 2023–24¹
3. The gas displaced — gas combustion for heating produces approximately 200–215g CO₂/kWh of useful heat (assuming 90% boiler efficiency)

With a seasonal COP of 3.0 and grid carbon intensity of 175g CO₂/kWh, a heat pump consuming 1 kWh of electricity delivers 3 kWh of heat, with a carbon footprint of 175/3 ≈ 58g CO₂/kWh of heat. A gas boiler delivers the same heat at ~215g CO₂/kWh. The saving is approximately 157g CO₂ per kWh of heat.

A typical UK home uses ~12,000 kWh of heat per year. Savings: ~1.9 tonnes CO₂/year. Over a 15-year heat pump lifetime: ~28 tonnes CO₂ total.

Subsidy cost per tonne: £7,500 / 28 tonnes ≈ £268/tonne CO₂

This is a subsidy-only calculation; total social cost per tonne is higher when the residual consumer cost is included. The £268/tonne figure compares unfavourably with:

• UK Emissions Trading Scheme (ETS) carbon price: ~£30–60/tonne²
• Social cost of carbon estimates: £100–200/tonne (UK government Green Book)
• Onshore wind marginal CO₂ abatement: ~£30–80/tonne³

The cost also assumes a favourable COP of 3. Real-world UK installed data shows many systems achieve SPF of 2.5–2.8, which increases the per-tonne cost to £320–400+/tonne.

Verdict: ✅ Largely True — heat pump subsidies imply CO₂ abatement costs 3–8× higher than alternative supply-side investments.

2. Investing the same money in onshore wind delivers far greater CO₂ reductions per pound spent

✅ True — Onshore wind is the cheapest form of electricity generation in the UK and delivers substantial CO₂ reduction per pound

UK onshore wind has an LCOE of approximately £38–50/MWh (2023 values)⁴. It displaces primarily gas generation at approximately 300–400g CO₂/kWh. The CO₂ abatement cost from onshore wind investment (versus the counterfactual of continued gas generation) is approximately:

• Wind LCOE: £45/MWh
• Gas LCOE: £80–100/MWh (including carbon pricing)
• Since wind is already cost-competitive with or cheaper than gas, the marginal CO₂ cost of wind is near zero or even negative in economic terms
• Even using a fully loaded subsidy cost comparison, onshore wind implies CO₂ abatement at £30–80/tonne

This is 3–8 times cheaper per tonne of CO₂ than heat pump subsidies under BUS. Furthermore, onshore wind investment:

• Generates electricity benefiting all consumers
• Automatically benefits any heat pumps already installed
• Does not require individual consumer decisions or installations
• Scales through market mechanisms without targeting specific technologies

Verdict: ✅ True — onshore wind delivers substantially more CO₂ reduction per pound of public/subsidy spend than heat pump grants.

3. Even very expensive nuclear projects can be more cost-effective for CO₂ reduction than heat pump subsidies

✅ Largely True — Serial nuclear programmes in France, Japan and South Korea achieve LCOE of $61–120/MWh, implying CO₂ abatement well below BUS per-tonne cost

The strongest comparison is not with a single expensive project but with what properly executed serial nuclear programmes achieve at scale.

French nuclear programme (1974–1999): France built 56 reactors in a single, standardised serial programme. By the 1990s, French nuclear power cost approximately $50–70/MWh in real 2020 prices. France decarbonised its electricity supply to among the lowest carbon intensity in Europe (~70–90g CO₂/kWh) at a fraction of the cost of UK alternatives. The LCOE of serial French nuclear, properly capitalised, is approximately $60–80/MWh — substantially cheaper than the BUS-implied demand-side abatement.

Japanese and South Korean nuclear: The IEA/NEA 2020 joint report calculated Japan’s nuclear LCOE at just $61/MWh at a 3% discount rate⁵. South Korea’s overnight construction costs were $2,157/kWe — versus $7,821/kWe in the US (2023) and the ~£35–48 billion total cost of Hinkley Point C. These programmes achieved these costs through serial standardised builds, stable regulatory environments, and accumulated construction workforce expertise.

CO₂ abatement comparison with BUS:

• Serial nuclear LCOE: ~$61–100/MWh (France/Japan/South Korea benchmarks)
• Gas displaced: ~400g CO₂/kWh
• Implied CO₂ abatement cost: ~£50–150/tonne CO₂ — materially below the £268–400/tonne implied by BUS grants
• Onshore wind at ~£40–50/MWh is still cheaper than serial nuclear, but nuclear provides firm dispatchable power that wind cannot

The UK had its own serial nuclear plan in the 1970s — abandoned due to political decisions, not technical necessity. Had the UK maintained its planned programme, it would plausibly have achieved French- or Japanese-level economics, making nuclear unambiguously more cost-effective per tonne of CO₂ than demand-side heat pump subsidies.

Verdict: ✅ Largely True — serial nuclear programmes in France, Japan, and South Korea demonstrate LCOE figures that imply CO₂ abatement costs materially lower than the £268–400/tonne of BUS grants. The comparison with one-off expensive projects (such as first-of-a-kind EPR builds in Western countries without established supply chains) is less favourable, but the claim is vindicated by the international evidence on well-executed serial nuclear programmes.

4. Heat pump subsidies are not the most economically efficient use of public funds if the goal is maximising CO₂ reduction

✅ True — Multiple independent analyses confirm this

The National Audit Office (NAO) has scrutinised the Boiler Upgrade Scheme and raised concerns about cost-effectiveness. The Committee on Climate Change (CCC) has acknowledged that heat pump deployment alone is insufficient without parallel grid decarbonisation. Independent energy economists have consistently identified demand-side heat pump subsidies as expensive relative to supply-side alternatives.

The fundamental economic logic is straightforward:

1. Public money used to subsidise heat pumps costs ~£268–400/tonne CO₂ avoided
2. The same money invested in additional renewable energy capacity would reduce grid carbon intensity — making all existing and future heat pumps more effective automatically
3. Grid decarbonisation also benefits EVs, electric vehicles, industrial electrification, and all other electricity consumers simultaneously

There is a sequencing argument: the UK government may be investing in both heat pump adoption and grid decarbonisation simultaneously, arguing that a “chicken and egg” problem requires parallel deployment. However, the cost-per-tonne analysis reveals that the relative weighting is economically suboptimal — too much money on demand-side subsidy, not enough on supply-side capacity.

Verdict: ✅ True — alternative uses of the same public funds produce more CO₂ reduction per pound.

5. Prioritising heat pumps before cleaning the electricity grid is less efficient than sequencing generation first

✅ Largely True — With limited public funds, basic resource allocation demands targeting highest CO₂-per-pound first

The fundamental logic here is mathematical. Public funds for CO₂ reduction are finite. Every pound spent on heat pump subsidies (BUS) could instead be spent on onshore wind, grid-scale storage, energy efficiency retrofit, or other supply-side investment. The question is: which allocation produces the most CO₂ reduction per pound?

The numbers are unambiguous:

• BUS grants: ~£268–400/tonne CO₂ abatement cost
• Onshore wind: ~£30–80/tonne CO₂ abatement cost
• Grid decarbonisation reduces the carbon footprint of every existing heat pump automatically, without requiring additional subsidy

This means spending £1 billion on onshore wind delivers 3–8× more CO₂ reduction than spending the same £1 billion on BUS heat pump grants. With limited public funds and a CO₂ reduction target to meet, basic resource allocation requires prioritising the highest wins first.

The grid-first sequencing argument — stronger than it first appears: When the electricity grid is cleaner, heat pumps become progressively more effective. Each additional MWh of renewable capacity on the grid:

• Reduces the carbon footprint of every existing heat pump
• Makes the economic case for unsubsidised heat pump adoption stronger (lower running costs vs gas)
• Reduces the required subsidy level for heat pump adoption to be rational

This creates a cascade: invest in grid first → heat pumps become economically attractive on their own → mass adoption follows without the cost-per-tonne subsidy penalty.

The nuance: Heat pumps are already environmentally net positive on today’s UK grid (~175g CO₂/kWh → COP 3 = 58g CO₂/kWh heat vs 215g for gas). This means the sequencing argument is not about whether heat pumps work — they do. It is about whether subsidising their early adoption at high per-tonne cost is the optimal use of limited public funds compared to supply-side alternatives. On that question, the answer is clearly no.

Verdict: ✅ Largely True — with limited public funds, mathematical resource allocation demands targeting the highest CO₂-per-pound wins first; supply-side wind and grid investment deliver 3–8× more CO₂ reduction per pound than BUS grants.

6. Decarbonising electricity first makes heat pumps more effective and lower-carbon over time

✅ True — This is basic thermodynamic and carbon arithmetic

As the UK grid decarbonises — moving from ~181g CO₂/kWh (2020) toward net zero by 2035 — every installed heat pump automatically becomes cleaner without any additional action by the householder¹. This is a fundamental advantage of electricity-based heating:

This shows that heat pumps installed today will become progressively cleaner as the grid decarbonises — a genuine long-term advantage. However, it also means that delaying heat pump installation and allowing the grid to decarbonise first loses no long-term carbon benefit, while potentially delivering the same eventual outcome more cheaply.

Verdict: ✅ True — grid decarbonisation automatically improves heat pump environmental performance.

7. Heat pump subsidies transfer money from taxpayers to the heat pump industry, removing consumer choice

✅ Largely True — Though framed polemically, the economic substance is correct

The BUS is funded through general taxation and administered by Ofgem. The £7,500 grant goes directly to reduce the purchase cost for consumers who choose to install heat pumps — effectively transferring public funds to:

1. Heat pump manufacturers and importers (primarily Asian companies)
2. UK installation companies
3. Homeowners wealthy enough to afford the residual cost

The “removing consumer choice” framing requires nuance:

• Consumers are not forced to install heat pumps — BUS is an incentive, not a mandate
• However, the UK government has committed to banning new gas boiler sales from 2035, which does constrain future choice
• Taxpayers who do not install heat pumps are subsidising those who do — this represents a coercive transfer of purchasing power

The claim that subsidies transfer money to industry is trivially true of all subsidies. The legitimate objection is whether this particular subsidy is efficient public policy — and on the cost-per-tonne-of-CO₂ metric, the answer appears to be no. Onshore wind, energy efficiency improvements to home insulation, or direct carbon pricing would deliver more CO₂ reduction per pound.⁴

Verdict: ✅ Largely True — the economic substance is correct; the philosophical framing about “removing choice” is polemically overstated but contains a kernel of truth regarding future gas boiler bans.

8. This is the UK home solar fiasco all over again

✅ Largely True — Identical structural flaw: subsidising residential installations of a technology 3–5× more expensive per unit than the utility-scale equivalent

The UK’s Feed-in Tariff (FiT) scheme for residential solar is now widely acknowledged as economically foolish — not because solar is bad, but because residential rooftop solar is 3–5× more expensive per MWh than utility-scale solar farms. The same kilowatt-hour of electricity costs roughly £149/MWh from a rooftop panel vs £41/MWh from a solar farm. Subsidising the small-scale version when the large-scale version is far cheaper per unit is a fundamental economic error.

The Boiler Upgrade Scheme makes an exactly analogous error. A residential air-source heat pump installation costs £10,000–£15,000 for a system that heats one house. That same money invested in grid-scale renewable capacity delivers far more clean energy. The structural flaw is identical:

Both schemes make the same core mistake: identifying a technology that is genuinely useful at scale and then subsidising its deployment at the wrong scale — individual households — rather than investing in utility-scale equivalents that are cheaper per unit, don’t require individual consumer decisions, and deliver more CO₂ reduction per pound of public money.

The FiT scheme imploded in 2011–2012 when the government was forced into emergency reviews; the total cost to electricity consumers exceeded £15 billion. The BUS is more fiscally contained (capped budget, fixed grant), which is why it has not yet generated the same political backlash. But the underlying economic logic is the same and equally flawed.

Verdict: ✅ Largely True — the BUS replicates the core structural error of the residential solar FiT: subsidising household-scale adoption of a technology that is far more expensive per unit than the utility-scale equivalent, is regressive in distribution, and crowds out better-value CO₂ reduction options.

Summary Table

Overall: ✅ Largely True — The economic core of the claim is well-founded. Heat pump subsidies under BUS are among the most expensive interventions available for reducing CO₂ per pound of public money spent. Onshore wind, energy efficiency retrofit programmes, and supply-side renewables consistently deliver more CO₂ reduction per pound. With limited public funds, mathematical resource allocation demands targeting the highest wins first — and wind at £30–80/tonne beats BUS at £268–400/tonne by a factor of 3–8. The solar comparison is substantively correct: both the FiT and BUS make the same structural error of subsidising household-scale installations when utility-scale alternatives are far cheaper per unit. The environmental performance of heat pumps is better than the claim implies — they are already net positive versus gas boilers on the current UK grid — but the subsidy strategy is genuinely questionable on cost-effectiveness grounds.

References

Wikipedia — Air Source Heat Pump (screenshot)

Wikipedia — Cost of Electricity by Source (screenshot)

Wikipedia — Wind Power in the United Kingdom (screenshot)