Salix: The Simplest Commercial Solar Finance for Public Sector
Salix 0% interest loans make commercial solar net-zero-cash for public sector bodies. Here is the process and the typical economics in 2026.
What Salix is
Salix is the UK Department for Energy Security and Net Zero's interest-free loan scheme for public sector energy-efficiency projects. Schools, NHS trusts, councils, universities and other state-funded bodies can borrow at 0% to fund solar PV, LED, insulation, controls and other net-zero capex. The loan is repaid out of the energy savings the project generates — typically across a 5-year term — leaving the public body owning the asset at end of term.
The maths in three lines
- Annual energy saving from solar = X
- Annual Salix repayment = Y
- X ≥ Y is the eligibility test; surplus stays with the public body
Worked example: 75kWp primary school install
The school's existing electricity bill is £18,400/year. After install:
- Annual electricity saving: £7,200
- Annual SEG income (summer holidays generation): £1,800
- Annual benefit: £9,000
- Salix loan (70% of £68,400 cost): £47,880
- 5-year repayment: £9,576/year
- Net cash impact during loan: approximately neutral
- Year 6+: £9,000/year of clear saving, school owns the system
Process and timeline
From initial enquiry to live system: typically 5-7 months. The breakdown:
- Site survey + project specification: 2-3 weeks
- Salix application drafting: 2-3 weeks
- Salix assessment: 8-14 weeks
- Offer + contracting: 4-6 weeks
- DNO G99 application (runs in parallel): 8-12 weeks
- Install: 1-2 weeks
- Commissioning + sign-off: 1 week
Who can apply
State-funded schools and academies, NHS trusts and arm's-length bodies, local authorities, police/fire services, universities and FE colleges, central government departments. Independent schools cannot. Some charities classified as public sector bodies can.
What KMM does
We project-manage the entire Salix application as part of our project fee — the application pack drafting, Salix correspondence, technical specifications, savings projections, contractor procurement evidence. We have delivered four Salix-funded school projects across the UK in 2025-2026.
Request a Fully Funded Electrical & Structural Survey
Tell us about your roof, your bills and your goals. KMM runs a fully funded electrical & structural survey, designs a system, runs the numbers and tells you honestly whether solar makes sense for you. No deposit, no pressure.
Fully Funded Survey → 0115 647 3822