How to Pay for Solar Panels UK 2026: Cash, Finance & Loans

The Four Ways to Pay (and One to Avoid)

Solar isn't cheap up front. A typical 4 kW system runs around £6,000, or about £11,000 once you add a 10 kWh battery. Here's how people actually pay for it, ranked roughly from cheapest to most expensive over the life of the system.

1. Cash. No interest, fastest payback, simplest sale if you move later.
2. Borrow against your home (further advance or remortgage). The lowest interest rate, because it's secured lending.
3. A solar loan or finance deal (0% or interest-bearing). Convenient, no need to touch your mortgage, but watch the APR.
4. Green Homes Wales loan (Wales only). Interest-free, £1,000 to £25,000, subject to credit and affordability checks. There is no Scottish equivalent for standard panels.
5. Leasing / "free solar". Avoid. You don't own the panels and it can hurt your home's value.

Use the calculator to see what finance actually costs you, and whether your savings cover the repayments.

Paying Cash

If you can afford it, this is almost always the best option. You pay roughly £6,000 for a 4 kW system and it's worth about £701 a year straight away: 3,800 kWh generated, 45% of it used at home at 26.32p (£450) and the rest exported at 12p on Octopus Outgoing (£251). That pays for itself in about 8.6 years, and everything after that is profit for 15+ more years. The full working is in our solar panel costs guide.

The honest counterpoint: £6,000 is a lot to tie up in your roof. If clearing a credit card debt at 24% or topping up an emergency fund is the alternative use for that cash, do those first. £701 on £6,000 is about a 12% return in year one against today's unit rate, which is excellent, but it isn't liquid and you can't get it back out in a hurry.

Borrowing Against Your Home

This is the cheapest way to borrow, and most people overlook it. If you have a mortgage, ask your lender about a further advance (borrowing a bit more on top of your existing mortgage) or roll it into a remortgage when your deal ends. Some lenders offer "green" further advances at a small discount for energy improvements.

Why it's cheaper: mortgage rates are far lower than personal loan or retail finance rates, because the debt is secured against your house. The trade-off is that spreading £6,000 over a 20-year mortgage term means you pay interest for a long time, so overpay it back faster if you can. And because it's secured on your home, missing payments is more serious than with an unsecured loan. For most homeowners with mortgage headroom, this still works out cheaper than a solar finance deal.

Solar Loans and Finance Deals

Most installers offer finance at the point of sale, and it falls into two camps.

0% APR deals

Genuinely interest-free finance does exist, usually on combined solar-and-battery packages, over shorter terms (often 2 to 3 years), and typically with a small deposit. If your savings cover the monthly payment, a 0% deal is almost as good as cash, you keep your savings in the bank and the system still costs you nothing extra. The catch is the short term means higher monthly payments, so check the figure works for you.

Interest-bearing solar loans

These spread the cost over 3 to 10 years, with representative APRs commonly in the 9 to 15% range. Over a long term that interest adds up fast: borrow £6,000 over 10 years at 10% and you'll pay back closer to £9,500. That's still workable if it's the only way you can go solar, but it eats into the return. Always compare deals by their APR (which includes fees) and look at the total amount payable, not just the monthly figure. And check it's regulated credit, so you have proper consumer protection.

Wales and Scotland: Cheaper Borrowing

Wales has the standout deal. Green Homes Wales offers interest-free loans from £1,000 to £25,000, repayable over up to 10 years, with a six-month upfront repayment holiday so the savings start before the repayments do. Solar PV, solar PV with a battery, solar PV with a diverter and solar PV-T are all on the eligible measures list, and there's a fully funded Retrofit Coordinator assessment up front (developmentbank.wales, checked 18 September 2026). An interest-free loan is effectively as good as paying cash: you keep your savings and pay it back gradually. If you're in Wales, this beats any finance deal an installer will offer.

The conditions are worth knowing before you get attached to the idea. There's no means test, but the home has to be in Wales, owned by you, your primary residence and not a new build under six months old. Listed buildings aren't currently supported, landlords can't apply, and every application goes through affordability and credit checks. Call Nest on 0808 808 2244 first for free advice, then register your interest with the Development Bank of Wales.

Scotland is more limited for solar. Home Energy Scotland does not fund standard solar PV, either by grant or by loan. What it does still fund is solar thermal at £5,000 and hybrid solar PV-T at £5,000, both grant only, alongside heat pumps and insulation (homeenergyscotland.org). So if you're doing panels on their own, Scottish homeowners rely on 0% VAT and the Smart Export Guarantee like everyone else. If you have a decent hot water demand, ask HES specifically about PV-T rather than "solar", because the answer to the second question is no and the answer to the first is £5,000.

England and Northern Ireland don't have an equivalent loan scheme yet. The government's Warm Homes Plan sets out a consumer loan scheme intended to deliver 0% or low-interest borrowing for solar, batteries and heat pumps to all homeowners regardless of income, but it isn't open, and gov.uk says only that eligibility and timing will be set out during 2026. Worth watching. Not worth delaying a sensible install for.

The 0% VAT Deadline Matters

Right now, solar panels and batteries fitted on a home anywhere in the UK carry 0% VAT, covering the panels, inverter, battery, scaffolding, cables and labour as a single install. That's a saving of £1,000 or more on a typical system. VAT Notice 708/6 says the relief runs on installations made between 1 May 2023 and 31 March 2027, and that "from 1 April 2027 onwards, supplies of installations of energy-saving materials will revert to the reduced rate of VAT of 5%" (gov.uk, checked 18 September 2026). There's been no announcement of an extension. It doesn't change how you pay, but it's a real reason not to drag your feet: the same system will cost roughly £300 more after that date.

What to Avoid: Leasing and "Free Solar"

If a company offers to fit solar "for free", read the small print. These are roof-lease or "rent a roof" deals: the company owns the panels, keeps most of the financial benefit, and you sign a 20 to 25 year lease. You get cheaper daytime electricity but none of the export income or real savings, and the panels never become yours.

The bigger problem is selling up. A buyer inherits the lease, and some mortgage lenders won't lend on a property tied to one. As we cover in our guide on whether solar adds value to your home, owned panels add value while leased panels can actively put buyers off. With 0% VAT and cheap finance available, there's almost no reason to lease today. Own the system, even if you have to borrow to do it.

The Bottom Line

Pay cash if you comfortably can, it's the fastest payback and the cleanest sale later. If you can't, borrowing against your mortgage is usually the cheapest route, a 0% finance deal is excellent if your savings cover the payments, and a longer solar loan still works as long as you go in with eyes open about the interest. In Wales, go to Green Homes Wales before you look at anything an installer offers. In Scotland, you're relying on 0% VAT and the Smart Export Guarantee. Wherever you are, own the panels rather than leasing, and get it done before the 0% VAT window closes on 31 March 2027.