Solar Finance Monthly Payments: Repayment Table (UK, 2026)

Quick answer: At an illustrative 8.5% APR, financing a £160,000 commercial solar system costs about £3,258 a month over five years, £2,509 over seven and £1,957 over ten. A useful rule of thumb at that rate over seven years is about £157 a month for every £10,000 financed. The monthly figure is only half the picture: set it against what the system saves and earns each month, and against the total cost of credit.

When a quote arrives, the monthly payment is the number a finance director looks at first, and it is hard to judge in isolation. A £2,500 monthly payment means one thing on a system that saves £3,300 a month and another on one that saves £1,800. This page gives you the repayment side of the sum for the common system sizes and terms, so you can tell quickly whether a quote is in the right range before you ask anyone to model it properly.

How the table is built

Every figure here assumes equal monthly payments in arrears, with no deposit, balloon, residual or fees. The rate is an APR, which is an effective annual rate, so the monthly rate used is (1 + APR) to the power of one twelfth, minus 1. The 8.5% is an illustration, not a market quote: the rate you are offered depends on the strength of your business, the term, how the deal is secured and its size, as we explain in what drives the cost of solar finance.

Monthly repayment at 8.5% APR

Installed cost	5 years	7 years	10 years
£50,000	£1,018	£784	£612
£100,000	£2,037	£1,568	£1,223
£160,000	£3,258	£2,509	£1,957
£250,000	£5,091	£3,920	£3,058
£500,000	£10,183	£7,839	£6,116

What the same finance costs in total

Installed cost	5 years	7 years	10 years
£50,000	£11,096	£15,852	£23,387
£100,000	£22,193	£31,703	£46,774
£160,000	£35,508	£50,725	£74,838
£250,000	£55,481	£79,258	£116,935
£500,000	£110,963	£158,515	£233,869

This is the total cost of credit: every repayment added together, minus the amount financed. A longer term lowers the monthly payment but raises the total, which is the trade you are making when you stretch a facility to make the monthly figure fit.

How much the rate matters

The same £160,000 system over six years at three illustrative rates:

APR	Monthly repayment	Total repaid	Cost of credit
6%	£2,640	£190,057	£30,057
8.5%	£2,820	£203,030	£43,030
11%	£3,003	£216,226	£56,226

Moving the rate by 2.5 percentage points in either direction changes the monthly payment by about £180 and the total cost of credit by about £13,000. That is a real number, but it is smaller than the swing from choosing a different term, which is why the structure deserves as much attention as the rate.

Flat rate against APR

Quotes are not always given as an APR. A flat rate is charged on the original balance for the whole term, so it understates what you are paying. A 5% flat rate on £160,000 over six years means £48,000 of charges, £208,000 repaid and £2,889 a month, which is equivalent to an effective APR of about 9.45%. Ask which one you have been given, and ask for the total cost of credit in pounds so the comparison does not depend on the label.

What the table leaves out

• Deposits, balloons and residuals. A final balloon payment lowers the monthly figure and moves the cost to the end of the term. Check the arithmetic, not just the monthly payment.
• Fees. Documentation and facility fees add to the true cost and are not in the figures above.
• VAT timing. With hire purchase or an equipment loan the VAT on the full price is paid up front and recovered on your next return, so it is a short-lived cash-flow item. With a lease it is charged on each rental instead.
• Tax relief. A company that owns the system can claim the Annual Investment Allowance, which at the 25% main rate relieves up to a quarter of the cost in year one. That cuts the net cost of ownership and is not in a repayment table.
• The saving. The other half of the sum is what the system saves and earns each month. If that is higher than the repayment, the project is cash-flow positive from the first month.

Putting your own numbers in

The tables give you a quick range. For your own figures, the solar finance calculator takes the cost, term, rate and your expected annual energy value and returns the monthly repayment, the total cost of credit, the year-one relief and whether the project pays for itself from month one. To convert the result into a cost per kilowatt-hour you can compare with a PPA, our guide to working out your solar cost per kWh does the division for you, and solar panel lease vs buy compares the rental route against owning.

To compare the same system under hire purchase, an equipment loan and a lease, with the tax effect, use the hire purchase, loan and lease calculator.

If a quote carries a balloon, solar hire purchase VAT and balloon payments shows what it does to the monthly payment and the total cost of credit.