The UK retail-finance market for solar in 2026 has three distinct strong cards plus a long tail of competent personal loans. The dominant story this year is that 0% APR is available to most homeowners — either via Nationwide's mortgage top-up or via an installer's own captive finance — provided the customer matches a small set of eligibility rules. Verified May 2026.
The published market
| Lender | Product | Term | APR | Amount | Gate |
|---|---|---|---|---|---|
| Nationwide | Green Additional Borrowing | 2 or 5 yrs fixed | 0% APR | £5,000 – £20,000 | Existing Nationwide mortgage, ≤90% LTV |
| E.ON Next | Solar finance | up to 3 yrs | 0% APR | Quote value | E.ON Next solar customer, ≥£12k income, DD |
| Octopus Energy + DivideBuy/Zopa | Solar BNPL | 2–3 yrs / 5–10 yrs | 4.9% APR (short) / 9.9% APR (long) | Octopus quote value | Octopus solar customer, £500 deposit |
| Tesco Bank | Clubcard Home Improvement Loan | 1–10 yrs | 6.0% (Clubcard) / 6.4% rep APR | £3,000 – £35,000 | UK resident, credit check |
| M&S Bank | Personal Loan | 1–7 yrs | 5.7% rep APR | £1,000 – £30,000 | UK resident, ≥£10k income |
Worked example — £12,000, 6 kWp + 10 kWh battery
All figures are net of the 0% VAT regime on energy-saving materials, which runs to 31 March 2027 and then reverts to 5% (gov.uk):
- Nationwide Green Additional Borrowing, 5 yrs at 0% — ~£200/month. Zero finance cost over 60 months. Mortgage-holder gated.
- E.ON Next 0% finance, 3 yrs — ~£333/month. No mortgage gate; works for renters' landlords or unmortgaged homeowners.
- Tesco Clubcard 10-yr at 6.0% APR — ~£133/month. Lowest absolute monthly payment in the market for anyone outside the Nationwide / E.ON gates. Total interest ~£3,990 over the life of the loan.
- M&S Bank 7-yr at 5.7% APR — ~£174/month.
- Octopus 9.9% APR over 10 yrs — ~£158/month, total interest meaningfully higher.
Stacking the cashbacks
Most major UK lenders pay a one-off cashback rather than a discounted rate. They stack with any of the above finance products:
- Halifax Green Living Reward — £1,000 cashback on solar/battery with a Halifax mortgage application after 31 July 2024.
- Lloyds Eco Home Reward — £1,000 (£2,000 for heat pump) with a residential mortgage illustration after the same date.
- Barclays Greener Home Reward — £500 or £1,000 depending on measure.
Smart Export Guarantee — the export side of the equation
Every supplier with 150,000+ domestic customers must publish an export tariff. Mid-2025 the best fixed rates sit around 15 p/kWh (British Gas, Good Energy, E.ON Next, EDF); Octopus Intelligent Flux averages around 27 p/kWh with a battery and time-of-use charging. On a 6 kWp + 10 kWh install, expect roughly £500–700/year of export revenue at the fixed rates and £950–1,200/year on Intelligent Flux — direct offset to the monthly loan payment.
The bottom line
If the customer is a Nationwide mortgage holder, Nationwide Green Additional Borrowing wins outright on total cost. For everyone else, E.ON Next's 0% over 3 years is the most genuinely free finance, and Tesco Clubcard's 10-year term drives the monthly payment to its lowest possible figure for a £12,000 install. All three benefit from the 0% VAT regime running to March 2027 and from the SEG export revenue.