Salix vs PSDS vs CIF: Which Funds Your School's Solar?

The funding decision an SBM actually has to make

Ask any school business manager (SBM) what stops a solar project, and the answer is rarely “we don’t want it”. It is “which pot pays for it, and am I about to back the wrong horse?” There are three serious national funding routes for school solar in England — the Salix Decarbonisation Loan, the Public Sector Decarbonisation Scheme (PSDS) and the Condition Improvement Fund (CIF) — plus the Smart Export Guarantee and regional mayoral schemes around the edges. The trouble is that almost no competitor explains cleanly which route suits which school. This guide fixes that.

The short version: your school’s legal status (maintained, academy, voluntary aided) and your appetite for a competitive bid decide the route. Salix is the default because it is not competitive and is available to almost every state school. PSDS and CIF are grants — free money — but you compete for them, and you only win with a strong, well-scoped bid. Below is the head-to-head, then the detail behind each column.

The three schemes at a glance

Scheme	Who’s eligible	What it gives	Cost to school	Competitive?	Best for
Salix Decarbonisation Loan	Maintained schools, academies, FE/sixth-form colleges	Interest-free loan, repaid from energy savings (up to ~8 years)	£0 interest; repaid from the savings the panels create	No — apply when ready	Any state school wanting a cash-flow-positive project without a bidding contest
PSDS Phase 4	All public-sector buildings, including schools and FE colleges	Capital grant, up to 100% of eligible measures	Nothing to repay if awarded	Yes — highly competitive	Larger projects, especially where solar is paired with heat decarbonisation
Condition Improvement Fund (CIF)	Academies, sixth-form colleges, voluntary aided schools, non-diocesan single-academy trusts	Capital grant (part or full)	Small expected contribution on some bids	Yes — annual round, scored	Academies pairing solar with roof refurbishment or fabric work

Read the table as a decision tree, not a menu. If you are a maintained community school, your realistic choices are Salix or PSDS. If you are an academy, you can add CIF to that list. Independent (private) schools sit outside all three and self-fund — covered at the end.

Salix: the interest-free default

The Salix Decarbonisation Loan is the workhorse of state-school solar, and for good reason. It is interest-free, and it is repaid from the energy savings the system delivers rather than from your teaching budget. The mechanics matter: because there is no interest and the repayment is pegged to savings, most well-sized school arrays are cash-flow positive from year one — the annual saving on your electricity bill exceeds the annual loan repayment, so the school is better off from the day the meter starts spinning backwards.

Key facts an SBM needs:

• Eligibility is broad — maintained schools, academies, and FE/sixth-form colleges all qualify.
• Loan sizes typically run from around £20,000 to £400,000 per project.
• Repayment is spread over a period up to roughly eight years, set against auditable energy savings.
• The application is not competitive. You are not bidding against other schools; you apply when your project is ready and the numbers stack up.

The one discipline Salix demands is an auditable energy-savings calculation. Salix needs to see that the project genuinely delivers the savings that repay the loan. This is where a specialist installer earns their keep: we build the savings model from your half-hourly (HH) meter data and hand you a defensible figure to submit. If Salix is available to you and you want certainty rather than a bidding contest, it is almost always the right starting point.

PSDS: the grant worth chasing at scale

The Public Sector Decarbonisation Scheme is different in kind. It is a capital grant — money you never repay — administered by Salix Finance on behalf of DESNZ. Phase 4 can fund up to 100% of eligible measures, with project values typically running from around £100,000 into the millions.

The catch is that PSDS is highly competitive, and the strongest applications are rarely solar on its own. PSDS is fundamentally a decarbonisation scheme, so bids that pair solar PV with heat decarbonisation — replacing gas boilers with air-source or ground-source heat pumps, improving building fabric — score far better than a standalone rooftop array. If your school is already contemplating a boiler replacement or a fabric upgrade, wrapping solar into a combined PSDS bid can be the single best-value route available. If you only want panels and nothing else, PSDS is a harder sell and Salix is usually the cleaner path.

CIF: the academy route, best paired with roofing

The Condition Improvement Fund is the grant route reserved for academies, sixth-form colleges, voluntary aided schools and non-diocesan single-academy trusts. It runs as an annual bidding round, and bid quality is everything. Solar qualifies under the condition and energy-efficiency criteria, but a bare “we’d like some panels” bid rarely wins.

Where CIF shines is when solar is paired with roof refurbishment. If your roof needs replacing anyway — and many pre-2000 school roofs do — bidding to refurbish the roof and mount solar in the same project reads as sound estate management to the assessors, not a nice-to-have. The condition case carries the energy case. Academies with an ageing roof and a net zero ambition should look hard at CIF before anything else.

The routes that fill the gaps

Two smaller mechanisms sit alongside the big three:

• Smart Export Guarantee (SEG) — not a capital route, but it monetises the electricity your school exports during holidays and weekends at 4–15p/kWh. It never funds the install, but it improves the lifetime economics that underpin every other route, and it matters more for term-time-only schools than most people assume. See our guide to the term-time over-generation problem for why.
• Devolved Mayoral Combined Authority schemes — regions such as Greater Manchester, the West Midlands and West Yorkshire run their own decarbonisation pots for public buildings, typically £25,000–£250,000. Worth checking your combined authority, as the pools change frequently.

What about independent schools?

Independent (private) schools are not eligible for Salix, PSDS or CIF — those are public-sector routes. Independents typically fund solar from reserves or low-cost bonds, and since VAT began applying to private-school fees in January 2025, capital discipline has tightened. That said, the payback case is often stronger for independents because boarding houses create a 24/7 baseload that lifts self-consumption well above a day-only state school. A no-upfront solar power purchase agreement (PPA) is also worth exploring — read our piece on whether a school can really get free solar for how that works. Our independent schools page covers the private-capital picture in full.

How to choose in practice

Line the three up against your own school and the answer usually falls out:

• Maintained community/foundation school, want certainty, no appetite for a bidding contest → Salix.
• Any public-sector school also replacing heating or improving fabric → PSDS combined bid.
• Academy or VA school with a roof that needs work anyway → CIF paired with roof refurbishment.
• Independent school → reserves, bonds, or a PPA — not the public schemes.

None of these routes is mutually exclusive across a wider estate, either. A multi-academy trust can run a single Salix or PSDS application across several schools at once — the economics are stronger at scale, as our trust procurement guide explains. For the wider funding landscape and the current scheme details, see our grants and funding page, and for what the numbers actually look like, our cost guide.

The next step

The funding decision is not one you should make from a blog post alone — it turns on your legal status, your roof condition, your heating plans and your metered load. What we can do is model all of it, build the auditable savings calculation Salix and PSDS demand, and tell you which route your specific school should back. Request a free feasibility and we will map the right funding combination to your status, your roof and your half-hourly data — and write the energy-savings case you sign, rather than leaving you to work it out alone.