Guide: solar
How much do solar panels cost in the UK?
There is no single honest answer, and anyone who gives you one without seeing your roof is quoting a marketing figure. What you can do is understand exactly what you are being charged for, so you can compare quotes properly and spot the lines worth arguing about.
Last reviewed: September 2026
Why we do not publish a national average
Average installed prices circulate widely and are repeated without a source or a date attached. We do not publish one, because the number has to carry so many caveats that it stops being useful: scaffolding on a three-storey terrace, a slate roof needing extra care, a long cable run to a meter at the far end of the house, and the choice between a string inverter and optimisers can each move a quote by a four-figure sum.
A figure you calculate from your own quotes is worth more than a figure you read on a website. The practical approach is to collect three quotes, break each one into the components below, and compare like with like.
What sits inside an installed price
Ask for the quote itemised. If an installer will not itemise, that is information too.
- 01Panels: the number of modules, the rated output of each in watts, the manufacturer, and the product and performance warranty terms.
- 02Inverter: the type (string, hybrid or microinverters), its rated output, and whether it is battery ready. A hybrid inverter costs more now and saves a second inverter later.
- 03Optimisers or microinverters: worth paying for on a shaded or multi-orientation roof, often not worth it on a clean single-pitch south-facing roof.
- 04Mounting and roof works: rails, brackets, flashings, and any tile or slate replacement. In-roof mounting costs more than on-roof.
- 05Scaffolding and access: a genuine cost, quoted separately by good installers, buried by others.
- 06Electrical works: DC and AC cabling, isolators, a generation meter if used, and any consumer unit upgrade or earthing work.
- 07Labour and commissioning: installation days, testing, system handover and documentation.
- 08Paperwork: MCS certification, DNO notification or application, and the Smart Export Guarantee documentation you need to sell surplus power.
- 09Optional battery: storage quoted alongside panels is a separate decision, and should be shown as a separate line so you can price the system without it.
Why two quotes for the same roof differ so much
- Different array sizes. A quote for 4.5 kWp and one for 6 kWp are not competing offers, they are different products.
- Different panel and inverter tiers, with warranty terms to match. Compare the warranty years and what they actually cover.
- Optimisers included in one quote and absent from the other, which is a real cost difference and sometimes a real performance difference.
- Scaffolding included, excluded, or assumed to be shared with other work.
- Roof complexity handled honestly in one quote and priced as a surprise later in the other.
- Battery bundled into the headline price, making the panel cost look higher or lower than it is.
- VAT treatment stated clearly in one quote and vague in the other. Ask for the VAT position in writing.
The lines worth challenging
Challenge the generation estimate first. It should be based on your roof orientation, pitch and shading rather than a generic figure per kWp, and the installer should be able to tell you which method produced it. An optimistic generation estimate quietly improves every savings and payback figure downstream.
Challenge the assumed self-consumption share next. The proportion of your generation you use at home rather than export is usually the single biggest lever on annual benefit, and it is the number most likely to be flattered in a sales spreadsheet.
Then challenge the extras. Bird protection, monitoring subscriptions, extended warranties and consumer unit upgrades may all be reasonable. They should still appear as priced lines rather than as an unexplained gap between two quotes.
Common mistakes
- Comparing headline prices instead of price per kWp installed, with the same inclusions on both sides.
- Buying the biggest array that fits when most of the extra output will be exported at a low rate.
- Accepting a payback figure without seeing the generation, self-consumption, import price and export price behind it.
- Treating a battery as part of the solar decision rather than as a separate purchase with its own arithmetic.
- Signing on a deposit before the DNO position and the scaffolding cost are confirmed in writing.
- Forgetting the export side entirely, then finding no Smart Export Guarantee tariff has been arranged.
Questions to ask before you sign
- 01Is this quote itemised, and can I have the panel, inverter and mounting specifications in writing?
- 02What annual generation are you predicting, how did you calculate it, and what shading did you assume?
- 03What self-consumption share does your savings figure assume, and what happens to the figure at a lower share?
- 04Is scaffolding included, and what happens to the price if access turns out to be harder than expected?
- 05Is the inverter battery ready, and what would adding storage later cost in practice?
- 06Who handles the DNO application and the MCS certificate, and when do I receive the documentation?
- 07What is the deposit, what is it protected by, and what are the cancellation terms?
Run your own figures
Once you have an itemised quote, the arithmetic is straightforward. Put your annual electricity use, your import price, the quoted system size, the quoted generation estimate, a realistic self-consumption share, your export rate and the installed cost into the calculator and see what benefit and payback fall out. Then reduce the generation and self-consumption figures by a sensible margin and look at the answer again.
If the decision only works at the optimistic end of both assumptions, it is a tighter decision than the quote suggests. See our methodology for what the calculator includes and deliberately leaves out.
Grants
Most households buying solar pay for it themselves. Some lower income households in England may be able to get solar through the Warm Homes: Local Grant, arranged by their council. Current scheme details, values and official source links are on our grants page, checked 15 September 2026.
Price your own roof
The calculator turns an itemised quote into an annual benefit and a payback figure, with every assumption visible and editable.