The decarbonisation of existing buildings is one of the major challenges facing the UK as it seeks to achieve its ambitious target of transitioning to net zero.
Much of the UK’s housing stock was constructed before the advent of modern energy-efficient standards. As a result, homes with low levels of thermal efficiency often require more energy to heat and can often be expensive to heat and costly to improve. Housing stock across the UK differs, with a wide variety of insulation, heating upgrades and other energy-efficiency measures being required to improve energy efficiency performance. Most of these improvements require substantial upfront investment, which is often prohibitive.
The challenge to deliver UK housing stock improvements is therefore not simply a matter of technological challenge. Delivering retrofit at scale requires additional sources of capital, alongside existing public funding and other forms of private investment. Recent estimates place the required funding needed to improve UK housing to a standard that may support a net zero target at between £300 and £500 billion, a figure that simply cannot be fully supported via the public purse.
PNZ Carbon developed its project to help address this unique funding challenge by creating a mechanism through which private sector climate finance can support UK housing decarbonisation. The project began in 2022, with an initial pilot delivered alongside project partner the Housing Associations’ Charitable Trust (HACT) and 22 social housing organisations. We are proud to have since expanded its impact across social housing, local authorities and the wider domestic retrofit sector. Expanding project scale has enabled support to be provided to thousands of individual retrofit activities, with associated emission reductions and social value independently verified via the Verified Carbon Standard.
Why support this project? Supporting the PNZ Carbon project directs climate finance into tangible decarbonisation and measurable social impact across local communities across the UK.
Creating Lasting Impact
For those organisations investing in the project, it provides a direct connection between carbon finance, independently verified carbon emission reductions and measurable positive outcomes for local communities across the UK.
Supporting UK Homes
The project focuses its support on low- and middle-income UK households, seeking to direct help to where it is needed most. Engaging with social housing providers, local authorities and private installers across the UK, the project is proud to now work with over 200 project participants.
Measuring More Than Carbon
Our project is unique in its impact calculation, as it measures more than simply tonnes of carbon emission reduction.
The decarbonisation of domestic properties can make our homes warmer, more affordable to heat and generally healthier to live in. The project measures these outcomes using the UK Social Value Bank, facilitating the formal quantification of the wider health and wellbeing impact associated with retrofit activity, alongside the associated achieved emission reductions. These social value calculations form part of the project’s independent verification assessment with VVBs.
Achieved Carbon Reductions
Unlike many projects that are based on projected future impact, carbon credits generated by the PNZ Carbon project originate from achieved, ex-post emission reductions and are issued only following independent verification under Verra’s Verified Carbon Standard.
High-Integrity Carbon Credits. Real UK Homes. Real Impact.
Follow the latest milestones and updates from this project.
The PNZ Carbon and HACT project was announced as part of National Grid’s Carbon and Nature Framework. The Framework is designed to provide an important new route for organisations to support high-integrity UK carbon reductions. The project is proud to have secured investment totalling circa 11,000 credit purchases from the Framework to date.
The project continues to enrol eligible retrofit activity across the UK, with subsequent emission reductions subject to ongoing monitoring and independent verification before credits are issued. Continued project growth is expanding both the project’s climate impact and its measurable social value, delivered through supporting the creation of warmer, healthier, more energy-efficient homes.
As the project grows from strength to strength, its monitoring approach was adjusted to facilitate the creation of two monitoring periods per calendar year. This allows for quicker movement through the third-party verification and Registry review process, allowing quicker distribution of supports to fund decarbonisation.
1st January 2024 – 31st December 2024
The project continued to scale rapidly, independently verifying a further 88,331 tCO2e of achieved emission reductions, with cumulative social value now breaking the £76 million milestone.
PNZ Carbon and HACT, and its joint project Retrofit Credits, was awarded the prestigious Ashden Award for Energy Innovation, recognising the innovation of its approach to financing the decarbonisation of UK housing.
1st January 2023 – 31st December 2023
The project successfully expanded into its first full-year vintage in 2023, expanding its impact in both the social housing and private domestic sectors. Increasing impact from circa 6,700 homes to circa 39,900 homes, the project confirmed a further 30,756 tCO2e of achieved emission reductions.
The first vintage for the project was completed via a pilot that was successfully deployed with the support of 22 local authorities and housing associations, quantifying achieved emission reductions of 1,481 tCO2e. Completion of the first monitoring period successfully demonstrated the project’s ability to calculate and verify emission reductions from domestic retrofit activity.
Developed in conjunction with HACT, the project launches with considerable initial participant and corporate buyer support. Launched under the Verified Carbon Standard, this marks the beginning of the project’s first (renewable) seven-year crediting period.
The project reduces greenhouse gas emissions by improving the energy efficiency of existing UK homes and reducing demand for fossil fuels.
Emission reductions are calculated at a property-by-property level and adjusted for external factors, including weather conditions. Credits originated by the project represent achieved, ex-post emission reductions and are issued only following independent third-party verification. All credits are issued under Verra’s Verified Carbon Standard.
By creating an additional source of finance for housing retrofit, carbon finance can also help overcome financial barriers to decarbonisation and support energy efficiency improvements being deployed more widely (and earlier) than might otherwise be possible.
Across its first three completed monitoring periods, the project calculated 120,568 tCO2e of independently verified emission reductions, including 88,331 tCO2e during 2024 alone. The project continues to scale its impact successfully and is planning two separate CY2025 vintages.
These Sustainable Development Goals show the wider outcomes this project supports beyond its headline impact.
Improving the thermal and energy efficiency of homes can help reduce the impact of fuel poverty, particularly for lower-income households. During the 2024 monitoring period, the project supported retrofit activity in 31,718 newly onboarded low-income households, reaching 66,994 in low-income households cumulatively.
Cold and inefficient homes can negatively affect physical and mental health. By improving homes' thermal and energy efficiency, the project supports better resident health and wellbeing.
Energy-efficiency improvements reduce the amount of energy required to heat and power participating homes. By supporting the deployment of retrofit measures, the project reduces household energy demand and improves energy efficiency.
The decarbonisation of UK homes has the potential to create jobs and strengthen existing businesses, particularly retrofit measure installers and their supply chains. Delivering retrofit activity at scale, as the project continues to support, also helps develop a skilled workforce as the UK transitions to a low-carbon economy.
The project supports innovation in the financing and delivery of housing decarbonisation, using carbon finance to help make retrofit projects more viable and accelerate investment in improving existing UK housing infrastructure.
A large proportion of project activity supports social housing and lower-income households. Improving access to warmer and more energy-efficient homes helps ensure that the benefits of the transition to a low-carbon economy can reach households that likely face the greatest barriers to funding any improvements directly.
Improving existing homes supports healthier, more efficient and more resilient communities. The project contributes to this goal by reducing the impact of fuel poverty and improving the quality and energy performance of housing across the UK.
Housing decarbonisation plays a critical role in the transition to a low-carbon economy. By supporting the deployment of retrofit activity more widely and cost-effectively, the project delivers independently verified greenhouse gas emission reductions while helping accelerate the UK’s targeted transition to net zero.
These partners help deliver the project and verify its impact.
The Verified Carbon Standard (VCS) Program is the world's most widely used greenhouse gas (GHG) crediting program.
