How to pay for solar: cash, credit, finance or mortgage

Why the protection matters more than the rate on this purchase

Solar is a purchase where things can go wrong long after the money has gone: an installer ceases trading before commissioning, the array underperforms against what was promised, the MCS certificate never arrives, or the roof leaks around a penetration.

The route you paid by decides what you can do about it.

Section 75 of the Consumer Credit Act makes the credit provider jointly and severally liable with the supplier for breach of contract or misrepresentation, for purchases over £100 and not over £30,000. In practice that means a claim against a solvent card issuer when the installer is not. Our section 75 page covers the conditions and the traps — including the one about paying an intermediary.

Section 66A gives the borrower under most regulated credit agreements 14 days to withdraw from the credit, without giving a reason. The period runs from the latest of the agreement being made, the creditor telling you the credit limit, or your receiving a copy of the executed agreement. Agreements secured on land, and agreements for credit over £60,260 other than residential renovation agreements, are excluded.

Note carefully: withdrawing from the credit is not the same as cancelling the installation contract. Those are two agreements with two sets of rights — see cancellation rights.

Cash

What it gets you: the strongest position in the negotiation. No finance commission is built into the price, and an installer who knows the money is not conditional on a lender has one fewer reason to inflate.

What it costs you: every credit-side protection. If the installer fails after taking your money, you are an unsecured creditor — see when an installer goes bust.

The compromise most people should consider: pay the deposit by credit card and the balance in cash. That preserves section 75 on the whole contract while keeping the cash discount on most of it.

And keep the deposit small. See deposit protection.

Credit card

What it gets you: section 75, in the cleanest form available.

What to check: that the payment goes directly to the supplier, because paying through certain intermediaries can break the debtor–creditor–supplier chain that section 75 depends on.

What it costs you: card interest if you do not clear it, which can be substantially more than dedicated finance.

Finance arranged by the installer

This is the default route, and the one to be most deliberate about — not because it is bad, but because of when it is offered.

Check the firm’s permissions. A business arranging credit generally needs Financial Conduct Authority authorisation or must be an appointed representative of an authorised firm. The Financial Services Register is public, free and takes under a minute.

Check whether the rate is subsidised. A 0% deal is being paid for by someone. If the installer is paying the lender a subsidy, that cost is in the price you were quoted — so ask what the cash price is. A meaningful difference tells you what the finance is actually costing.

Do not sign on the day. You have a 14-day withdrawal right on the credit under section 66A, and separate cancellation rights on the contract, but the cheapest way to use them is not to need them. The full set of tactics is in solar finance: the traps, and the pressure techniques worth recognising are in doorstep sales.

Buy-now-pay-later

The regulatory position changed this year, and anything written before 2026 on this is out of date.

The Financial Conduct Authority’s policy statement PS26/1, published 11 February 2026, brings Deferred Payment Credit into regulation from 15 July 2026, with firms lacking consumer credit permissions required to register for a Temporary Permissions Regime from 15 May. The stated aims are information requirements, affordability standards, and support for borrowers in financial difficulty.

We could not establish from the policy statement itself whether section 75 and Financial Ombudsman access attach in the same way as to other regulated credit, or how pre-existing agreements are treated. Ask the provider directly, and get the answer in writing before agreeing to anything.

Borrowing against the house

Usually the lowest rate on offer, for the obvious reason: it is secured.

Three things to weigh, none of which we can weigh for you:

• A longer term can cost more in total even at a lower rate.
• The debt is secured on your home. That changes what happens if you cannot pay.
• Section 66A does not apply to agreements secured on land, so the 14-day withdrawal right is not there.

If you are considering a further advance, a remortgage, or a lender’s “green” product, that is a conversation with a mortgage adviser — a regulated activity, and one this site does not perform.

The VAT deadline, whichever route you choose

Installation is zero-rated for VAT until 31 March 2027, reverting to 5% from 1 April 2027 under HMRC’s guidance. On a median 4 kW installation that is around £320. It applies to the installation, not to a finance arrangement, but it changes the total you are financing.