Solar Panel Finance: 0% Loans, Mortgage Borrowing, Cash or Waiting for the Government Loan

There are four realistic routes: pay cash, take the installer's finance (often 0% for a few years), add the cost to your mortgage through a green borrowing product, or wait for the government's promised low-interest loans.

Most installers and energy suppliers now offer finance. Octopus, for example, lets you spread the cost with a fixed-term loan through Zopa Bank or pay in full after installation, with a £500 non-refundable deposit either way.

Here's how the four routes compare for a typical £7,000, 4kWp system in Greater Manchester:

Monthly figures are simple divisions of £7,000 with no fees. Compare any quote's price against the benchmark in our solar panel cost guide before you look at the finance.

Only if the system price is the same as the cash price. Lenders pay for 0% offers somehow, and some installers build that cost into the quote. Ask for a cash price and a finance price side by side; if they differ, the difference is your interest.

Check the price per kWp too. A 4kWp quote well above the MCS benchmark of £1,565–£1,785 per kWp needs explaining, whether you pay cash or not. Our quote checker does the maths for you.

Not on a short term. A 4kWp system in Manchester saves about £698 a year, or £58 a month, on our payback calculator assumptions. Borrowing £7,000 over 3 years at 0% costs about £194 a month, so you'd be around £136 a month out of pocket until the loan is paid off.

That's the trade-off people on r/UKPersonalFinance weigh up: one poster considering a £10,000 0% loan at about £300 a month was told the maths works only if they stay in the house long enough. A longer term brings monthly costs closer to the savings, but usually at a higher rate once any 0% period ends.

It can be the cheapest borrowing available. Nationwide's Green Additional Borrowing lends £5,000–£20,000 at 0% fixed for 2 or 5 years, with no product fees, for solar panels and storage among other upgrades. You need to be an existing Nationwide mortgage member who has held the mortgage for at least 6 months, and the total can't exceed 90% of your home's value.

The catch comes after the 0% period: any balance moves to Nationwide's Standard Mortgage Rate, currently 6.49%, unless you switch product. Plan to repay or remortgage before then. Other lenders offer green mortgage incentives, so ask your own lender first.

Probably not. The Warm Homes Plan sets aside up to £1.7 billion for low- and zero-interest consumer loans for solar, batteries and other upgrades, but as of September 2026 Sunsave reported no confirmed launch date, rates or eligibility rules.

Meanwhile the clock is running on VAT: solar and batteries are zero-rated until 31 March 2027, then 5%. Waiting also means missing months of bill savings. Plenty of r/SolarUK readers have asked whether to hold fire for the government loan; the answer depends on whether you can afford to install now without it.

Pay at least the deposit on a credit card. Section 75 makes the card provider jointly liable for purchases over £100 and up to £30,000, even if only part of the price went on the card. That matters if the installer later fails; see what to do if your solar company goes bust.

Read any finance agreement for early repayment terms, and check the installer is MCS-certified and backed by deposit insurance. If you might qualify for funded panels instead, check our Greater Manchester grants guide first, and consider whether a battery is worth financing too. For a cash-price quote to compare, get in touch.