Solar panels: a UK guide for homeowners

Solar panels, also called solar PV, turn daylight into electricity for your home, so you buy less from the grid and can be paid for what you send back to it. A typical home system of 3 to 6 kWp costs about £6,300 to £9,900 fully installed, going by the government's cost data for 2025/26. In our calculator's London example, a 4 kWp system costing £7,100 on a home using 2,500 kWh a year pays for itself in about 12 years with a 12p export tariff, which needs Octopus as your electricity supplier. If you keep your current supplier and export at 6p, it takes about 19 years. At 12p, which needs Octopus as your electricity supplier, with electricity prices rising 2% a year (an assumption, not a forecast), it takes about 12 years. All three use October 2026 prices; the assumptions are below.

What solar panels are and what they do

A solar PV panel produces electricity; a solar thermal panel heats water instead. In a PV system, the panels produce direct current (DC) in daylight, and an inverter (one box, or microinverters behind each panel) converts it into the alternating current (AC) your home uses. Your home uses solar power first; the surplus goes to the grid, where a smart meter records it so a supplier can pay you, and the grid covers the rest, at night for example.

Two units appear on every quote. kWp (kilowatt-peak) is the panels' combined rated power under standard test conditions: the size of the system. kWh (kilowatt-hour) is energy produced or used over time: what saves you money. A 4 kWp system does not produce 4 kWh every hour; in London it produces about 4,000 kWh over a year.

Go deeper: how solar panels work, panel types, microinverters or a string inverter, panel sizes and weights and the best solar panels.

How much electricity solar panels produce in the UK

A south-facing roof tilted at 35° produces roughly 890 to 1,070 kWh a year for each kWp of panels, depending on where you live. These are long-term averages from the European Commission's PVGIS tool, which our calculator uses; a single year can be sunnier or duller.

Edinburgh beats Manchester in these figures. Output peaks in summer: a south-facing panel in London produces about 3.4 times as much in July as in December, and in Edinburgh about 5 times as much.

In London, PVGIS gives about 818 kWh per kWp for an east-facing roof and 787 for a west-facing one, roughly a fifth less than south-facing. Shade can cut output sharply (shading); heat costs a little efficiency but summer sun more than makes up for it (hot weather). To size a system from your bill and roof, see how many solar panels you need.

What solar panels cost

The government's latest cost data, for systems fitted to existing homes in Great Britain between April 2025 and March 2026, gives an average of £2,109 per kW for systems up to 4 kW and £1,651 per kW for systems of 4 to 10 kW. So 3 kWp costs about 3 × £2,109 = £6,300, and 6 kWp about 6 × £1,651 = £9,900. These averages include installation, grid connection and VAT, and exclude batteries.

VAT. Panels and batteries supplied and fitted by an installer in your home currently carry 0% VAT, until 31 March 2027; after that the rate is due to become 5% unless the government extends the relief. Panels or kits bought without installation, including plug-in kits, carry the standard 20%. See VAT on solar panels.

Batteries. Our estimate for a battery fitted with the panels is about £3,200 for 5 kWh and £4,200 for 10 kWh; solar battery cost covers other sizes and adding one later.

The solar panel cost guide has prices by size and region and a checklist of what a quote should include, and comparing solar quotes shows how to line quotes up.

What solar panels save, and how long they take to pay back

Solar power saves money in two ways, worth very different amounts:

1. Electricity you use at home saves the unit rate on your bill: 26.32p per kWh on average under the Ofgem price cap for Direct Debit customers, 1 October to 31 December 2026. The standing charge does not change.
2. Electricity you export earns your export tariff. Octopus Outgoing pays 12p per kWh but needs Octopus as your electricity supplier on a compatible tariff; E.ON Next Flex Export pays 6p to anyone (both checked on 24 September 2026; suppliers can change these rates).

A kWh used at home is therefore worth 2.2 times a kWh exported at 12p, which needs Octopus as your electricity supplier (26.32p ÷ 12p), and 4.4 times one exported at 6p (26.32p ÷ 6p). That is why running the washing machine or car charger while the sun is out pays.

Worked example: London, 4 kWp, no battery. An illustrative estimate from our calculator, not a quote.

First-year value is the bill saving plus export: £185 + £405 = £589 at 12p export, which needs Octopus as your electricity supplier, or £185 + £202 = £387 at 6p with any supplier (after rounding). At 12p, which needs Octopus as your electricity supplier, a rough payback is £7,100 ÷ £589 = 12 years; the calculator adds each year's value with output falling 0.4% a year, which gives 12.3 years. Payback is before any repairs or a replacement inverter.

A household at home in the day uses more of its own power and does a little better; one out all day does a little worse. For Manchester and Glasgow examples and the downsides to weigh, read are solar panels worth it?. To choose an export tariff, see the Smart Export Guarantee and the best export tariffs we checked.

Should you add a battery?

A battery stores solar power you would otherwise export, so you can use it in the evening. Whether it pays depends mostly on how much electricity you use and when. Our calculator's Manchester example is a household using 3,600 kWh a year, out for half the day, with 5 kWp of panels:

At 12p export, which needs Octopus as your electricity supplier, the battery adds £207 a year for £3,200 more, so payback gets slightly longer. At 6p it gets shorter, because the power the battery saves for the evening would otherwise earn only 6p. For a home with typical use, a battery mainly moves daytime solar into the evening. Homes with an electric car or a heat pump use far more electricity, and on a cheap overnight tariff a battery can also charge from the grid at night: that is where batteries earn most. Our guide to tariffs for solar and batteries compares them.

The solar battery storage guide explains sizing, tariffs and backup in a power cut. See also battery prices, the best solar batteries and reviews of battery makers such as Tesla Powerwall, Fox ESS, Sigenergy and BYD. If you want a battery without panels, see home batteries without solar.

Planning, grid connection and certification

Planning. In England, panels on a house are usually permitted development, so you do not need to apply, if they meet the conditions: on a pitched roof, for example, they must not stick out more than 0.2 metres from the slope. Permitted development does not cover a listed building, which needs consent, and in a conservation area panels cannot go on a wall, balcony or roof enclosure that fronts a road. In Scotland, panels on a house or flat may protrude up to 1 metre, with limits in conservation areas; permitted development does not apply to listed buildings or in World Heritage Sites. Wales and Northern Ireland have their own rules; our planning permission guide covers each nation.

Grid connection. In Great Britain, smaller home systems connect under a rule called G98, which covers systems whose inverters, including any battery inverter, add up to no more than 16 amps per phase (3.68 kW on a normal single-phase supply): your installer tells your network operator no later than 28 days after switching on. A larger system needs approval before connection under G99, which takes longer. In Northern Ireland your installer registers the system with NIE Networks.

Certification. In Great Britain, suppliers' Smart Export Guarantee tariffs for a home system need an installation certified under the Microgeneration Certification Scheme (MCS) or an equivalent scheme. Before you sign, an MCS installer must give you in writing a performance estimate for your roof, the panel and inverter datasheets and a drawing of the layout. On MCS's redeveloped scheme, which most installers are moving to during 2026, belonging to a consumer code such as RECC or HIES is no longer required; instead the installer must give you a written guarantee for the design and workmanship and MCS-approved financial protection. If you want a code's extra protections, such as RECC's limits on deposits, check membership on the code's own website. See our MCS certificate guide.

Help with the cost in each nation

Most households pay for solar panels themselves, with 0% VAT on an installed system. Grants are targeted at lower-income households, and schemes and export rules differ by nation.

Be wary of "free" solar offers: a deal where a company keeps ownership of the panels or the export income does not give you free panels. The Warm Homes Plan guide explains the government's grants and the loans that are launching.

Plug-in solar: a small start

If you rent, live in a flat or want to try solar first, a plug-in kit is the small option. Since 27 August 2026 you can plug one into an ordinary socket in Great Britain, if it meets the government's product specification, puts out no more than 800 W and has no battery. That is a fifth of the capacity of a 4 kWp roof system (0.8 ÷ 4). The plug-in solar guide covers the rules, costs and output, and plug-in solar kits compares what is on sale.

Is solar right for your home?

The more of these apply, the stronger the case.

• Roof. Facing roughly south, east or west, with little shade, and not due for replacement for many years.
• Time. You expect to stay long enough to reach the payback point.
• Daytime use. Someone is at home in the day, or you can run appliances, a hot water tank or a car charger while the sun is out.
• Export tariff. You will switch supplier for a better export rate, or accept a lower open rate.
• Permission. You own the house, or the freeholder or landlord agrees, and you have planning or listed building consent where needed.

From first estimate to export payments

1. Estimate. Find your yearly electricity use on your bill and try our calculator for your address (Great Britain for now).
2. Compare installers. Ask more than one MCS-certified installer to survey the roof and quote. Our guides to choosing a solar installer and comparing solar quotes show what to check.
3. Compare the paperwork: performance estimates, equipment, warranties, payment schedule and who deals with the network operator. If you sign at home or online, the law lets you cancel from signing until 14 days after the equipment is delivered; choosing a solar installer explains your rights.
4. Installation typically takes one or two days. The installer issues the MCS certificate and, for a G98 system, tells your network operator.
5. Export tariff. In Great Britain, apply to a supplier for its Smart Export Guarantee tariff with your MCS certificate and a smart meter that records exports.

Living with solar panels

Panels have no moving parts and need little attention. The two panel datasheets we checked carry a power warranty of 25 or 30 years: a promise of minimum output, not an end date. The inverter has its own warranty, so check its terms. Glance at your monitoring app now and then, and leave any cleaning or roof work to a professional with proper access equipment. See maintenance, cleaning and how long solar panels last.

More guides

• Tariffs: Octopus Outgoing, Octopus Flux and Intelligent Octopus Flux.
• Who installs: the best solar companies and reviews of Octopus, E.ON and Hive.
• Roofs: solar roof tiles, in-roof panels and flat roofs.
• Panels and brands: the most efficient panels, AIKO, LONGi, JA Solar, Enphase and every brand we cover.
• Batteries: Tesla Powerwall 3 prices.

Frequently asked questions

What are solar panels made of?

Mostly silicon cells behind toughened (tempered) glass, in an aluminium frame, with a sealed junction box and cables on the back. Both datasheets we checked list 3.2 mm tempered front glass, an anodised aluminium alloy frame and an IP68-rated junction box; the JinkoSolar one lists N-type monocrystalline silicon cells.

What is the biggest drawback of solar panels?

Timing. Panels produce most at midday and in summer, when many homes use least, so much of the power is exported for far less than you pay for electricity: in our London example only 17% is used at home. Using more in daylight, a good export tariff or a battery all help. The other drawback is the upfront cost: in our London example (4 kWp costing £7,100, 2,500 kWh a year), payback takes about 12 years at 12p export, which needs Octopus as your electricity supplier, and about 19 years at 6p with any supplier.

How many solar panels do you need to run a house?

A typical home uses about 2,500 kWh a year, and a 4 kWp system, about nine 450 W panels, produces about 4,080 kWh a year in London. But panels cannot run a house on their own: in our example they cover about 28% of the home's use, because much of it falls in the evening, at night and in winter. See how many solar panels you need.

How much do 12 solar panels cost in the UK?

With 450 W panels, 12 panels make 5.4 kWp. At the government's 2025/26 average of £1,651 per kW for home systems of 4 to 10 kW, that is 5.4 × £1,651 = about £8,900 installed, before any battery. Panel wattages differ, so compare quotes by kWp rather than panel count.