The usual procedures within the Department were followed with S.I. 2026/368 and the correct version of the S.I. was signed by the Minister.

However, during the drafting process several versions of the S.I. were created to correct several minor formatting issues, and on examination an incorrect version of the S.I. was then laid before Parliament and published. Whilst the Lawmaker software used to draft S.I.s system may have contributed to the generation of multiple versions of the S.I., it was human error that led to the failure.

The Department has taken steps to address these issues, and has also reviewed improvements to the process to ensure that the version that is sent for registration is clearly identified and confirmed as the correct version.

We have been clear on several occasions that we will not force anyone to rip out a working boiler to deliver our carbon budgets, including in the Warm Homes Plan that we published earlier this year. Instead, this Government is focused on incentivising moves to cleaner, affordable heating and making this attractive and easy for the public.   Our Warm Homes Plan supports investment in heat pumps and other energy efficiency upgrades to help cut bills.

UK heat pump sales hit a record high in 2025, and the government expects to see continued growth over the coming years.

Manufacturers of a range of heating technologies, including fossil fuel boilers, are among the leading players in this growing market.

The government will continue to keep developments in the market under close review as heat pump uptake in existing and new homes continues to gather pace.

The Government’s Warm Homes Plan (WHP) - which represents the biggest ever investment in home upgrades, is an offer for every household.

Park home residents can apply for support via a range of Government schemes including the Warm Homes: Local Grant, and ECO4 - which Government intends to extend until the end of the year, subject to Parliamentary approval. All eligible households in England and Wales can benefit from the expanded Boiler Upgrade Scheme, funded with £2.7 billion to 2030. BUS provides grants up to £7,500 to help households with the upfront costs of installing heat pumps and biomass boilers. In addition, the 0% VAT rate on heat pumps installations offers further financial support.

We are also working with the finance sector to make a range of low-cost finance solutions available to homeowners, with Government backing a total loan portfolio of £2 billion, including up to £1.7 billion from our new Warm Homes Fund.

Residents who are not directly supplied with electricity may also be eligible for support with their bills through the Park Homes Warm Home Discount scheme.

The cost estimates used in the Clean Energy Campaign are based on the total energy for a home with a gas boiler including both gas and electricity costs (e.g. for lighting and appliances). Details for the assumptions behind the analysis are provided in the section marked “*How we calculated heat pump savings” on the campaign web page https://cleanenergy.campaign.gov.uk/heat-pump/. The analysis in the campaign assumed an annual gas demand of 12,200kWh, which is well aligned to OFGEM’s ‘Medium’ typical domestic consumption value of 11,500kWh.

The Carbon Budget and Growth Delivery Plan sets out the government's proposals and policies to enable carbon budgets to be met. In doing so, it provides an assessment of the impact of the government’s expectation that the vast majority of heating system replacements will be low-carbon by 2035.

We are making significant progress towards this objective. Demand for heat pumps and other clean technologies is soaring, while our Warm Homes Plan sets out ?15 billion of investment and a range of interventions to ensure that clean heating technologies are the most attractive and natural option for consumers.

The Clean Heat Market Mechanism does not require a change in the price of fossil fuel boilers.

The Government took steps to change earlier proposals for the design of the Clean Heat Market Mechanism ahead of its launch in April 2025 to reduce the potential impact on boiler manufacturers and provide them more time to scale up supply chains.

The Government delivers a number of digital services to support consumers with energy efficiency and clean heat, including 'Find Ways to Save Energy in your Home' (www.gov.uk/improve-energy-efficiency), providing tailored recommendations for home improvements. A phoneline service is available on 0800 098 7950.

Residents living in park homes are eligible for support under the Energy Company Obligation (ECO4) until it closes in March 2026, and the Warm Homes: Local Grant (WH:LG).

Energy cutting and bill saving measures available under the WH:LG include heat pumps and insulation. The WH:LG has been allocated £500 million to be delivered from 2025-2028 by participating local authorities.

Park homes may also be eligible for BUS funding providing all scheme eligibility criteria are met. Consumers can access further information, including eligibility criteria, at www.gov.uk/government/collections/find-energy-grants-for-you-home-help-to-heat.

Neither the department nor the Building Safety Regulator (BSR) hold figures on boiler sales.

Figures held by the BSR show 1,089,862 total gas appliance work notifications between 1 October 2024 and 30 September 2025 under the Gas Safe Register scheme. Of this total, 1,039,920 was for central heating natural gas boiler installations. This is more than 95% of the total gas installation work. A much smaller number of other gas boiler installations, such as for water heaters or warm air heating appliances, were also registered.

The Gas Safe Register scheme is run by the Health and Safety Executive but the BSR has access to the scheme’s installation registration numbers.

The BSR regulates other installation schemes, also called competent person schemes, which include installation of non-gas types of boilers but neither the BSR nor the department hold figures specifically on non-gas boiler installations.

Local authorities must make available to the public details of building control notifications in their area including for boiler installations.

We recognise that we need to support households struggling with bills whilst we transition to clean power by 2030. This is why we delivered the Warm Home Discount to around 3 million eligible low-income households last winter. On 19 June 2025, we announced that we are expanding the Warm Home Discount to around an additional 2.7 million households. This means that from this winter, around 6 million low-income households will receive the £150 support to help with their energy bills.

We are also delivering improvements to home energy efficiency through a number of schemes including the Warm Homes: Social Housing Decarbonisation, Warm Homes: Local Government and the continuation of the Boiler Upgrade Scheme, which is supporting thousands of households to upgrade their heating systems. As more homes are made energy efficient this will reduce carbon emissions, reduce overall energy demand and reduce energy bills for consumers.

The Department will receive independently verified sales data after the conclusion of the first scheme year, in summer 2026, and data on the full compliance cycle for that scheme year in late 2026.

The government is continuing to assess the options for publishing certain Clean Heat Market Mechanism scheme data, for instance aggregate verified annual data, taking into account the commercial sensitivities of different approaches.

Approved Document L provides statutory guidance on how to comply with Part L, including advice on adding an inhibitor when a heating system is installed and on providing maintenance information to homeowners through a home user guide.

Checks or re-dosing of inhibitors during routine servicing are outside the scope of the Building Regulations where no building work is being undertaken. The safe installation, maintenance and use of gas systems and appliances are covered by the Gas Safety (Installation and Use) Regulations 2018.

The Government intends to amend Part L and its accompanying guidance in the coming months. The new standards, known as the Future Homes Standard, intends to effectively preclude the installation of gas boilers in new homes and ensure the use of low-carbon heating systems such as heat pumps.

The Department will receive independently verified annual gas and oil boiler sales data from scheme participants after the completion of each scheme year via the scheme’s administrator, the Environment Agency. Further detail on these reporting processes can be found in the published scheme guidance. It also has access to heat pump installations data from the Microgeneration Certification Scheme and publishes statistics on Government-supported installations at https://www.gov.uk/government/collections/heat-pump-deployment-statistics.

The Department is considering the options to publish some Clean Heat Market Mechanism scheme data, for example aggregated annual verified sales and installation data, but needs to assess commercial sensitivities in doing so.

Heat batteries, sometimes referred to as ‘battery enabled boilers’, can utilise time-of-use tariffs and do not require outside space; however, they are less efficient than heat pumps. Heat batteries could meet the needs of some smaller homes, however if they do not have sufficient storage capacity they could draw electricity at peak times, adding burden on the electricity network and increasing energy bills.

Government will continue to review our position on heat batteries, as the supporting evidence base develops, including considering evidence from the Homes for Net Zero project.

Between January 2013 and April 2025, 889,589 boilers and 13 biomass boilers were installed under the Energy Company Obligation.

Between May 2022 and May 2025, 407 vouchers for biomass boilers were granted under the Boiler Upgrade Scheme.

No boilers were installed through the Home Upgrade Grant, Local Authority Delivery scheme, the Social Housing Decarbonisation Fund or Great British Insulation Scheme.

Only biomass boilers are eligible for support under the Warm Homes: Local Grant and Warm Homes: Social Housing Fund. The schemes started delivery in April 2025 and therefore installation figures are not yet available.