A new study from Cranfield University provides a system level lens on this debate. Rather than comparing technologies only at the level of individual homes, the research asks a more consequential question: which pathway minimises total national energy demand and therefore makes the broader transition to a net zero carbon energy system more achievable? The answer is unequivocal. Heat pumps hold a decisive advantage.

The physics that shapes policy
At the heart of the debate lies a simple but powerful reality: efficiency. Heat pumps do not generate heat in the conventional sense. Instead, they move it – extracting ambient warmth from the air or ground using electricity. Their performance is typically measured by a seasonal performance factor (SPF), which commonly ranges between 200% and 400%. In practical terms, that means for every unit of electricity consumed, a heat pump delivers two to four units of usable heat.

Hydrogen boilers, by contrast, operate much like today’s natural gas boilers. They burn fuel to produce heat. But when the hydrogen is ‘green’ – produced by splitting water using electricity via electrolysis – the chain of energy conversions introduce substantial thermal losses. Electricity is first converted into hydrogen, typically losing around a third of the energy in the process. The hydrogen must be compressed, transported or stored, before finally being burned in a boiler that itself is less than 100% efficient.

The result is an unavoidable thermodynamic gap. Heat pumps multiply energy. A hydrogen system degrades it.

That gap, modest at the scale of a single dwelling, becomes enormous when magnified across 29 million UK homes.

A whole-system perspective
The Cranfield study uses an end-state decarbonisation resource analysis (EDRA) framework to explore this difference at the national scale. EDRA does not simulate transition pathways. Instead, it assumes the UK has reached full decarbonisation by 2050 under specified technological configuration, and then calculates the generation capacity, infrastructure, land use and capital associated with that system.

The model assumes that:

• The UK achieves complete energy independence and all energy is produced domestically.
• Baseload electricity demand is met by nuclear power to ensure system stability – a role currently performed by natural gas.
• Wind, solar, hydro, tidal, wave and non-biodegradable waste provide additional zero carbon electricity.
• Offshore wind is the main renewable generation technology, as it delivers the highest power output among all renewables in the UK.
• Hydrogen is produced from surplus renewable electricity and stored in underground salt caverns for use in hard-to-abate sectors and grid balancing.
• Direct electrification dominates in most sectors outside residential heating.
• Waste heat is recovered where feasible.

This deliberately ambitious ‘fully decarbonised’ vision provides a clean comparison between a heat pump scenario in which homes are heated primarily by heat pumps, and a hydrogen scenario in which homes are heated primarily by hydrogen boilers. All other sectors remain identical in both scenarios.

Demand: the hidden multiplier
The most striking difference between the two pathways lies in primary energy demand – the energy contained in raw sources before it is converted into consumable energy.

Compared with today’s fossil fuel-based system, a heat pump share of 82% in homes would reduce the UK’s primary energy demand for domestic heating by more than 50%.

Under a conservative assumption of a national average SPF of 2.54, the reduction is estimated at 53%.

By contrast, replacing gas boilers with hydrogen boilers at the same scale would increase home heating demand by more than 42%, even assuming a relatively high hydrogen boiler efficiency of 94%.

The divergence in electricity demand is even more dramatic. To meet identical heating needs, the hydrogen pathway would require more than three times as much electricity as the heat pump pathway.

In a fully decarbonised energy system – where every kilowatt-hour must be generated by zero carbon sources such as renewables or nuclear power – this multiplier effect directly dictates how much infrastructure must be built. More electricity demand means more wind farms, more nuclear reactors, more grid expansion, more electrolysers and backup power plants, and more land or sea areas devoted to energy production.

Demand reduction at the point of use, therefore, becomes a strategic lever. The technology chosen for home heating does not merely warm buildings; it reshapes the entire energy economy.

Generation capacity: a question of scale
Under the heat pump scenario, assuming onshore wind and solar meet the government targets of 29 GW and 70 GW respectively, the UK would require around 102 GW of offshore wind and 71 GW of nuclear power by 2050.

The implied build rate for offshore wind – about 4 GW/y – is broadly aligned with the current government ambitions for 2030. Nuclear expansion, at nearly 3 GW/y, remains formidable but not inconceivable within a coordinated industry strategy.

Under the hydrogen-dominated scenario, however, the picture shifts dramatically. Offshore wind requirements double to 206 GW. Nuclear capacity rises to 91 GW. Offshore wind deployment would need to exceed 8 GW/y – far beyond historical build rates and the current policy targets.

This issue is not theoretical potential. The UK has world-class offshore wind resources. The question is whether such expansion can be delivered within 25 years while also upgrading grids, training skilled workers, securing supply chains and maintaining public consent. The hydrogen pathway stretches feasibility to its limits.

Infrastructure: beyond the turbines
Generation capacity tells only part of the story. A hydrogen-heavy system demands a parallel build-out of supporting infrastructure. Compared to the heat pump pathway, the hydrogen scenario requires around 50% more total capacity in electrolysers, combined-cycle hydrogen turbines used for backup power and electricity grids, as well as over 27% more large-scale, long-duration hydrogen storage.

The result is a far larger and more complex system. Implementing parallel electricity and hydrogen systems increase engineering complexity and capital exposure. It also heightens delivery risk.

The physical footprint of the energy system expands accordingly. In the hydrogen scenario, offshore wind farm area more than doubles relative to the heat pump pathway. The required sea area approaches 6% of the UK’s total marine territory.

While offshore wind enjoys broad support, scale matters. Marine ecosystems, fisheries, shipping lanes and coastal communities would also feel the impact of a system built at hydrogen scale.

On land, additional substations, electrolysers and hydrogen infrastructure compound the spatial burden.

Capital investment requirements follow the same pattern. For generation assets alone, the hydrogen pathway requires around 60% more capital than the heat pump pathway.

In energy system analysis, large upfront investments are converted into annualised costs, which distribute capital spending across the lifetime of assets to reflect the yearly costs of financing and operating them.

Measured in this way, the hydrogen pathway results in approximately £58bn more in annualised costs each year.

Compared to the current fossil fuel-based system, the heat pump pathway delivers estimated annualised generation cost savings of around 42%. The hydrogen pathway achieves only 7%.

In other words, the economic advantage of heat pumps is nearly six times greater than hydrogen boilers.

These figures do not account for every variable, but the direction is clear: higher energy demand drives higher system cost.

Hydrogen’s strategic role
Importantly, the study does not dismiss hydrogen as irrelevant. On the contrary, the EDRA framework assumes hydrogen is indispensable for aviation and shipping, heavy industrial processes, long-duration energy storage and grid balancing during prolonged low-renewable periods. Hydrogen is essential in hard-to-decarbonise sectors.

The question is not whether hydrogen has a role, but where that role delivers maximum system value. Using hydrogen extensively in home heating consumes scarce zero carbon electricity that could be more effectively deployed elsewhere. Prioritising heat pumps for homes frees up hydrogen for sectors where alternatives are limited.

The Cranfield study’s verdict is clear. If Britain wishes to minimise resource strain, contain costs and improve the feasibility of its 2050 ambition, heat pumps should form the backbone of residential decarbonisation, with hydrogen reserved for the sectors that truly need it.

The views and opinions expressed in this article are strictly those of the authors only and are not necessarily given or endorsed by or on behalf of the Energy Institute.

• Further reading: ‘Smart heat pumps: the potential for demand flexibility in the home’. A new study has demonstrated the transformative potential of smart heat pumps, not just as efficient heaters, but as powerful tools to support the management of the UK’s electricity system.
• ‘Hydrogen and ammonia in Europe – from hype to maturity in 2026?’ The long-term outlook for clean hydrogen and ammonia projects in Europe looks promising, but last year saw several setbacks around commercial viability and competition from oil and gas. However, the regulatory environment remains positive.