Summary

Let Zero is the UK’s first retrofit support service designed specifically for the private rented sector. Piloted in South Yorkshire and currently in a growth phase, it helps landlords improve energy efficiency in their properties through tailored advice, grants information, and trusted installer referrals. The service combines digital tools, local partnerships, and tailored support to overcome barriers to retrofit. Let Zero has supported over 60 landlords and carried out in depth retrofit assessments of 32 homes, and developed a ‘Show Home’ private rental property showcasing cutting edge retrofit technologies.

What problem are we trying to solve?

Private rented homes are among the least energy-efficient in the UK, with many tenants living in cold, damp conditions. Landlords face financial, regulatory, and practical barriers to retrofit, while tenants often lack the agency or support to advocate for improvements. Existing retrofit services rarely cater to the unique challenges of the PRS, and uptake of grants remains disproportionately low. Without targeted support, many landlords may exit the sector, worsening housing shortages and undermining climate goals.

How are we doing this?

Let Zero offers a ‘One-Stop Shop’ structured, landlord and tenant-facing service that includes:

• Initial advice and EPC review, and grant eligibility checking
• Home survey and development of Home Action Plan, and support sourcing installers
• Support navigating the installation process, tenant liaison support and education, and ensuring that the work on site meets the highest standards.

The service is supported by a retrofit project management platform developed by Pure Leapfrog with technology partner Bravand. The Centre for Energy Equality (CEE contributed valuable insights, and AI powered tools from Planerific, and rich data sets from Sustenic fed into the design. Quality assurance is built into every stage, with alignment to PAS 2035 and continuous feedback loops.

Let Zero conducted extensive stakeholder engagement with tenants, landlords, and other stakeholders such as letting agents, energy advice organisations and mortgage brokers during the pilot phase to inform the service design and potential referral pathways.

Who are we working with?

The pilot phase of Let Zero was led by the South Yorkshire Mayoral Combined Authority and funded by Innovate UK. Pure Leapfrog developed and delivered the service alongside specialist partners: Building Research Establishment (BRE), the Centre for Energy Efficiency (CEE), Sheffield Hallam University, the University of Sheffield’s Advanced Manufacturing Research Centre, Sustenic, and Planarific. Companies involved in showcasing retrofit technology in the Show Home include: Wrapt Homes, Trust Electric Heating, ICAX and VundaHaus. Key collaborators include:

• Local authorities across South Yorkshire (Doncaster, Barnsley, Sheffield, Rotherham)
• Retrofit installers and supply chain partners
• Energy advice organisations and tenant groups

The growth phase is a partnership between South Yorkshire Mayoral Combined Authority and Pure Leapfrog.

What is the innovation?

Let Zero is the first retrofit one-stop-shop in the UK designed specifically for the private rented sector. Innovations include:

A tailored customer journey for landlords and tenants, taking into consideration compliance pressures and financial realities

Navigator software, built to manage retrofit projects and support service delivery

A pre-screening model that enables landlords to see the potential for energy efficiency improvements across their portfolio, and understand grant eligibility

A quality assurance framework with real-time monitoring and feedback

Area-based scoping using drone and AI-powered tools

A replicable service model with plans for national rollout

What did we learn?

• Landlords are cautious but willing to engage when services are clear, trustworthy, and financially viable
• Grant uptake in the PRS is low due to complexity, mistrust, and lack of tailored support
• Tenants face structural barriers to engagement, including power imbalances and housing instability
• Trusted intermediaries and community-based approaches are essential for tenant outreach and engagement
• Quality assurance is critical, especially when working with grant-funded installations
• Local authority partnerships are key to reaching landlords and embedding services
• A flexible, replicable model is needed to scale retrofit support nationally

Results

In the pilot phase, Let Zero has:

• Held 40 energy efficiency cafes
• Supported 62 landlords
• Conducted basic assessments for 238 properties
• Carried out in-depth retrofit assessments for 36 properties
• 16 energy efficient measures installed including solar PV, internal and external wall insulation and air source heat pumps
• Delivered a ‘Show Home’ showcasing cutting-edge retrofit technologies with tenants in situ
• Built a comprehensive service that is ready to be rolled out at a wider scale.

What’s next?

The project is currently in a growth phase, building on the success of the pilot, working to build a sustainable, long-term, commercial service with ambitions to expand nationally.

Testimonial 

Pure Leapfrog brought expertise and an open mind to the thorny issue of engaging private landlords to carry out energy efficiency improvements. They experimented, refined and improved, delivering a one-of-its kind service which achieves results – very impressed with their work.

Malcolm Ramsay,

Project Manager, Housing, Infrastructure and Planning

South Yorkshire Mayoral Combined Authority