DESNZ: The Government Department Behind Home Energy Policy

The Department for Energy Security and Net Zero (DESNZ) is the UK government department that owns the policy behind how homes in Great Britain are heated and insulated. It sets the rules and budgets for the Boiler Upgrade Scheme, it developed the Renewable Heat Incentive that preceded it, it sets the overall policy for the Great British Insulation Scheme, and it backs the Energy Technology List of verified energy-efficient products¹. It was created in 2023, when it replaced the Department for Business, Energy and Industrial Strategy (BEIS) and took over BEIS's energy portfolio¹.

The department matters to a household for two reasons. First, almost every grant, standard and target that shapes what you can install in your home, from heat pump grants to installer certification, originates in DESNZ policy. Second, DESNZ is not the regulator: Ofgem administers and polices many of the schemes DESNZ designs, and the split between the two decides who you contact when something goes wrong. This page sets out what DESNZ is responsible for, what powers its Secretary of State holds, and where the department's reach stops.

The department's remit

DESNZ's responsibilities for households run wider than most people assume, because the department sits behind both the money and the rules. On the Boiler Upgrade Scheme, its responsibilities include the scheme policy and legislation, approving and publishing the standards, including consumer codes, that installers and products must adhere to, setting the scheme budget and publishing budget allocations for vouchers annually and quarterly if required, and determining, publishing and reviewing the grant categories and their values². On the Domestic Renewable Heat Incentive it was responsible for developing the underpinning policy, including setting tariffs, establishing the legislative framework and introducing amendments to the scheme³. Ofgem administers both schemes day to day, but the design, the money and the rule changes come from DESNZ.

The same pattern holds for insulation. The Department of Energy Security and Net Zero is responsible for setting the overall policy for the Great British Insulation Scheme⁴. And on products, the Energy Technology List, a scheme featuring over 8,000 independently verified and accredited energy-efficient products across 62 sub-technology groups, is backed by DESNZ, which annually reviews the technologies and products that qualify for inclusion⁵.

Beyond schemes, the department measures the country it governs. The DESNZ Public Attitudes Tracker tracks public awareness, attitudes and behaviours relating to the department's policies, such as energy and climate change¹¹. It has also worked jointly with Ofgem: the Heat networks regulation: implementing consumer protections consultation was published by DESNZ and Ofgem in November 2024¹². For a fuller picture of how the department's work sits alongside the regulator's, see UK home energy regulation and policy and Ofgem: what the energy regulator does.

What the Secretary of State can do

The Secretary of State at the head of DESNZ holds specific legal powers, not just political influence. Under section 212 of the Energy Act 2004, the Secretary of State may give financial assistance to the scheme administrator, make payments to the scheme administrator otherwise than as financial assistance in pursuance of arrangements under section 212(1), and guarantee the discharge of any financial obligation incurred by the scheme administrator in connection with those arrangements¹³. The same section allows the Secretary of State to make regulations conferring or imposing specified powers or duties on scheme administrators¹³. In practice this is the legal machinery behind government funding of bodies such as Ofgem in its scheme administrator role.

Secondary legislation adds further powers with built-in limits. Under the 2015 regulations, a direction made by the Secretary of State is disallowed if a specified process is not completed within a period of 28 days beginning with the date on which the direction is made¹⁴. Where the Secretary of State is considering exercising the call-in power over an energy project, written notice, described as the pause notice, must be given to the relevant local planning authority¹⁴. These are checks on the department's reach, and they matter to households mainly when a decision about local energy infrastructure is pulled up to Westminster.

The political leadership sets the direction. Ed Miliband was appointed Secretary of State for Energy Security and Net Zero in July 2024, and Sarah Jones was appointed Minister of State in the department, as well as in the Department for Business and Trade¹⁵. Ministers change; the statutory powers described above do not depend on who holds the office.

Installer capacity and the annual 600,000 heat pump goal

The single most quoted DESNZ number for households is the heat pump target. The department aims to reach 600,000 heat pump installations per year by 2028⁶, a figure that appears consistently across official documents: the Heat and Buildings Strategy committed to scaling up the installation of heat pumps to 600,000 installations per annum by 2028¹⁶, the Heat and Buildings Strategy committed to growing the supply chain to a minimum market capacity of 600,000 heat pump installations per year by 2028⁶, and the Net Zero Strategy metric is to achieve a minimum market capacity of 600,000 heat pumps per year by 2028¹⁷. The Heat Pump Net Zero Investment Roadmap expects annual deployment of heat pumps to reach at least 600,000 a year by 2028¹⁸, and the British Energy Security Strategy repeats the 600,000 figure¹⁹.

Progress is far short of that. The Environment Committee reported in 2025 that the previous Government set a target to install 600,000 heat pumps per year by 2028 and up to 1.9m per year by 2035, and that the CCC reports current installation rates are around one tenth of this²⁰. The department's own projections reach further: DESNZ projects that annual deployment of heat pumps will need to climb, potentially reaching up to 1.6 million installations per year by 2035²¹. A later factsheet gives an aim of 450,000 annual installations per year by 2030, 70% of which are targeted to be manufactured in the UK by 2035²². The differing end dates explain the differing numbers: 600,000 by 2028 is the near-term commitment, and the 2030 and 2035 figures are later projections under different plans.

The installer workforce is the bottleneck. DESNZ faces a substantial challenge to increase the number of trained heat pump installers to support an elevenfold increase in heat pump installations⁶, and the Government has acknowledged it will need to significantly increase the number of trained installers to deliver the 2028 target²³. The department had a target to reach 12,000 trained heat pump installers by 2025, but by May 2024 it had trained 7,000 installers so far, including 3,000 as part of the Heat Training Grant⁸. It stated it was investing £29 million from 2021-22 to 2024-25 to train installers in the heat sector⁶. The Public Accounts Committee also found that low uptake caused DESNZ to underspend by £100 million in the first year of the Boiler Upgrade Scheme⁶.

For households, the practical effect is that the grant framework exists but the delivery chain is still being built. Anyone looking to install a heat pump should do so irrespective of where they live, the department has said⁸, but finding a trained installer depends on the local supply chain that target is meant to create. More detail on the target itself is on What is the UK target for heat pump installations?.

A 2026 verdict on hydrogen for home heating

Hydrogen is the one big heating question DESNZ has deliberately left open. The Government committed in its October 2021 Heat and Buildings Strategy to decide on the role of hydrogen for heating in 2026⁶, and the Heat and Buildings Strategy states: "we intend to take strategic decisions on the role of hydrogen in heating buildings in 2026"²⁴. The Public Accounts Committee reported in 2024 that it remained the case that a decision on hydrogen should be taken in 2026⁶, and the department was still working towards being able to make a strategic decision in 2026 as of May 2024⁸.

The evidence-gathering has been troubled. DESNZ's work to test hydrogen for heating has been beset by problems, with key trials cancelled⁶, and the Public Accounts Committee noted that one cancelled trial meant there could not have been a live trial of hydrogen supply to non-domestic properties⁶. The department has instead drawn on other sources of evidence, such as a trial to use hydrogen for home heating across a neighbourhood in Fife, alongside trials in other countries, such as the Netherlands and Germany⁸. It has been working with the Health and Safety Executive to develop an evidence base around the safety and appropriateness of hydrogen to inform its 2026 decision⁸.

The department's stated position on the overall shape of heating is that heat pumps and heat networks will be the main low-carbon heating technologies over the next decade, with the potential for hydrogen to play a role in slower time in some locations⁶. The Energy Innovation Needs Assessment for heating and buildings, commissioned by DESNZ and delivered by a consortium led by the Carbon Trust, forms part of the evidence base⁷. For households on the gas grid, the practical message is that no decision forcing hydrogen into homes has been taken, and the full policy position is covered on Hydrogen for home heating: the policy position.

Reforming consumer protection: three principles, one regulator

DESNZ designed the current consumer protection system for home upgrades in response to the 2016 Each Home Counts review, introducing a single quality mark delivered by TrustMark²⁵. By its own admission, the system has not worked. The Department accepted that the system was too layered, fragmented and complicated, and that it had not provided the protection that consumers deserve²⁵.

Ministers have set out three principles for future reform of the system: the system must be simpler and clearer; there must be stronger central oversight with appropriate sanctions; and there must be real accountability with clear redress and remediation²⁵. The reform consultation proposes that DESNZ will have central oversight of the new consumer protection system for DESNZ-supported schemes, with a new integrated consumer protection service for government-supported home upgrades covering advice, quality assurance and redress, and with the responsibility potentially delegated to the Warm Homes Agency, subject to final approvals²⁶. DESNZ would act as the service integrator to ensure that operations are efficient, effective and provide a consistent, high-quality experience for consumers, installers and retrofit professionals²⁶.

The pressure for reform came from failure as well as design. The National Audit Office found that when DESNZ and Ofgem became aware of issues with energy efficiency installations under the Energy Company Obligation, they responded quickly, but the two challenges DESNZ now faces are to ensure that the relevant businesses meet their obligations to remediate all the affected homes as quickly as possible and to reform the system so that this cannot happen again²⁷. The department did not complete a full fraud risk assessment before ECO4 was implemented in 2022; it has since been completed and is actively managed, with all risks allocated to owners as of October 2025²⁵. It only escalated concerns to its Net Zero Buildings Portfolio Board in January 2025, once they had materialised²⁵. As of March 2025, retrofit coordinators are required to physically visit each project site²⁵.

Consumer redress is also being widened at the edges. The Energy Ombudsman, which has now helped one million consumers, announced reforms from DESNZ on 17 June, with Martin McCluskey as Minister for Energy Consumers²⁸. How the pieces fit today is explained on Energy complaints and redress and TrustMark: the government-endorsed quality scheme.

From £1.4bn resource budget to £13,381m overall

The money tells the story of the department's expansion. The Heat and Buildings Strategy promised a record level of investment of £6.6 billion on clean heat and energy efficiency over that Parliament¹⁶. The Spring Budget 2023 set out the department's resource departmental expenditure limits in current prices: £1.4 billion, then £1.6 billion for 2023-24, then £1.5 billion for 2024-25⁹. Its capital budgets were larger and rising: £4.7 billion, then £5.9 billion for 2023-24, then £8.2 billion for 2024-25⁹.

By 2025-26 the departmental group's total departmental expenditure limit was £13,381m²⁹. The difference between the 2023 plans and the 2025-26 total reflects both the capital ramp-up already visible in the 2023 figures and the growth of the department's portfolio since.

Figures from Spring Budget 2023, plans in current prices⁹.

Within that, specific commitments include £29 million from 2021-22 to 2024-25 to train installers in the heat sector, and some £868 million invested in heat networks up to 2028, including £338 million to 2025 and £530 million between 2025 and 2028⁶. Set against that, the £100 million underspend in the first year of the Boiler Upgrade Scheme shows that budget allocated is not the same as budget spent⁶. For households, the significance is that grant money exists but is drawn down only when households actually apply, so underspend is a signal about demand as much as about policy.

Schemes DESNZ inherited or operates

DESNZ did not start with a blank sheet. It inherited a portfolio of household schemes from BEIS, which itself had inherited some from the Department of Energy and Climate Change. The lineage matters because documentation, email addresses and legal frameworks often still carry the old names.

• Boiler Upgrade Scheme. DESNZ owns the policy, legislation, standards, budget and grant values; Ofgem administers².
• Domestic Renewable Heat Incentive. DESNZ is responsible for developing the underpinning RHI policy, including setting tariffs and the legislative framework³. From February 2023 DESNZ became responsible for RHI policy in GB; BEIS held it until 2023 and DECC until 2016¹.
• Great British Insulation Scheme. DESNZ sets the overall policy for the scheme⁴.
• Assignment of Rights. Introduced by the former Department for Business, Energy and Industrial Strategy, now DESNZ¹⁰.
• Energy Technology List. Backed by DESNZ, updated monthly, with annual reviews of qualifying technologies⁵.
• Feed-in Tariffs. FIT policy complaints go to the Complaints Manager, Enquiry Unit, Department for Energy Security and Net Zero, 1 Victoria Street, London, SW1H 0ET, or by telephone on 0207 215 5000³⁰.

If you need to deal with the department directly, the rules are strict. DESNZ will not talk about your case with you: you must put your points in writing³¹. It can take a few months for DESNZ to reply to your complaint³¹. For Green Deal matters the department still uses the email address gdconsumers@beis.gov.uk, a surviving BEIS address³¹. On review, DESNZ might decide to write off your Green Deal, reduce it, award you compensation, offer a settlement figure, or reject the complaint³¹. On deadlines, DESNZ might give you more time, but it does not have to³¹. The history of closed and abandoned policies is covered on Closed and abandoned home energy policies.

Missing levers for meeting carbon budgets

The Heat and Buildings Strategy commits the Government to "meet our legally binding carbon budget contributions, including carbon budgets and net zero commitment"¹⁶. The accountability problem, as Parliament's committees have set out, is that DESNZ owns the target but not all the levers, and several of the levers it does own have slipped.

The clearest example is levy rebalancing. Moving levies from electricity to gas bills, which would make running a heat pump cheaper relative to a gas boiler, has been delayed by nearly two years, with the department due to set out its approach during 2024⁶. The Public Accounts Committee also found DESNZ delayed its delivery target to pull together the different plans for decarbonising power from December 2023 to mid-2024, against its ambition to decarbonise the power sector by 2035⁶, and that the committee had called for a power sector delivery plan by autumn 2023 at the latest⁶.

Other gaps are structural rather than delays. DESNZ is still to work out how it will support households to decarbonise their homes where heat pumps are not a practical solution⁶. Its work on the costs and feasibility of gas network decommissioning was in the initial stages, with a consultation underway with Ofgem to identify the early issues⁶. The department has shifted its emphasis towards the importance of spatial planning, considering overall energy demand at a local level and how to connect low-carbon generation to individual homes⁸, and work is underway with the National Infrastructure Commission to look at how to build capacity in the distribution network operators to manage the increase in demand for energy, both nationally and at the street level⁸. DESNZ is also evaluating uptake of the Boiler Upgrade Scheme grant among different socio-economic groups, with interim results due in the second half of 2024⁶.

For a household deciding whether to act now, the lesson from this gap is that the framework is still moving. The carbon budgets are legally binding¹⁶; the policies to deliver them in heat are not all in place. How the budgets themselves work is explained on Carbon budgets, net zero targets and the Climate Change Committee.

Implications for household energy self sufficiency

DESNZ sits at the centre of what a home in Great Britain is allowed, helped and encouraged to do about its own energy. The grants that cut the cost of a heat pump, the standards that make an installer trustworthy, the targets that shape what manufacturers build and what training exists: all of it traces back to this department. A household that understands DESNZ's role knows where a scheme's rules come from, why a grant value changed, and who to write to when a government-backed upgrade goes wrong.

The dependence that remains is real, and it runs in several directions. A household taking a DESNZ grant depends on the department's budget allocations and its willingness to keep the scheme open, as the £100 million first-year underspend of the Boiler Upgrade Scheme shows how fragile the link between policy and uptake can be⁶. It depends on the department's delivery record: the delayed levy rebalancing means electricity remains relatively more expensive than the policy intended⁶. And it depends on decisions still pending, above all the 2026 hydrogen decision, which will shape whether the gas network has a long-term future for heating²⁴.

Against that, the direction of policy is consistent across documents of different vintages: heat pumps and heat networks as the main technologies for the next decade, hydrogen possible in some locations later, and a consumer protection system being rebuilt around a single overseer⁶. A household investing in insulation, a heat pump or solar now is moving with the grain of DESNZ policy rather than against it, and the more of the work a home can fund and choose itself, the less it depends on the next policy announcement. The rules that apply at home, and what they allow, are set out on Regulation and energy independence.