The price of a home system from three sources, what it saves with and without the Smart Export Guarantee, and the planning rules as they stand. Sources opened by me on 20 September 2026; no installer behind this page and no lead selling.
A typical home system of 4.5 kWp, around 12 panels, costs around £7,600 installed according to the Energy Saving Trust. The government counts what installers actually charged: on existing homes in 2025/26 the average was £1,651 per kW for systems of 4 to 10 kW, which works out at about £7,430 for the same 4.5 kWp. MyJobQuote puts a 4 kW system at £6,500 to £8,000. You pay 0% VAT until 31 March 2027. With export payments the Trust works out a payback of 9 to 12 years, on panels that should last 25 years or more.
Government figures: financial year 2025/26, Great Britain, averages from the MCS installation database; equipment, installation, connection and VAT where applicable, no battery. The last row is my own sum, not a source.
The estimate and the count land close to each other, and one of them is a count of what people really paid. The government notes that the cost per kW is lower for larger installations, which is why the small band sits higher. Prices have been falling: the median for 4 to 10 kW went from £2,067 per kW in 2023/24 to £1,546 in 2025/26, all installations counted.
Source: MyJobQuote, 25 August 2026; panels, hardware, inverter, labour and scaffolding at 0% VAT. A price guide that sells leads, used here as a measurement only.
A 4.5 kWp system covers 20 to 30 square metres of roof. An unshaded roof facing south is ideal; facing east or west it yields around 15 to 20% less, and the Trust does not recommend a roof facing north.
Source: Energy Saving Trust, savings per year for a four bedroom detached house, gas-heated, fuel prices as of July 2026. Payback is with export payments.
The Smart Export Guarantee has existed since 1 January 2020. It requires some electricity suppliers, which Ofgem calls SEG licensees, to pay you for what you send back to the grid, for installations in Great Britain up to 5MW. The supplier sets the tariff, it must always remain above zero, and you may pick any licensee, not just the company that supplies you (Ofgem). The table shows why it is worth the form: in London, out all day, £900 a year with an export tariff against £200 without.
These are the rules for England from the Planning Portal. The permitted development right was updated on 27 August 2026, with a transitional period ending on 27 August 2027 in which you may follow the old rules or the new ones. Leaseholders may need permission from the freeholder. For the rest of your project there is the planning permission check.
Installed panels and batteries carry 0% VAT until 31 March 2027; from the day after it is 5% (VAT Notice 708/6). There is no dedicated solar grant. The other schemes and their deadlines are on the grants page. Pairing panels with a heat pump? The heat pump check tells you whether your house is ready, and the quote check reads an installer's quote line by line.
Between 9 and 12 years with export payments, says the Energy Saving Trust: 9 years in London, 10 to 11 in Manchester and 11 to 12 in Stirling. Those figures are for a four bedroom detached house on the fuel prices of July 2026. Without an export tariff the yearly saving in London falls from £930 to £330 for someone who is home all day, so the payback gets a lot longer; the Trust does not publish that number and I do not make one up.
The Energy Saving Trust says panels should last 25 years or more. The inverter is the part that goes first: it needs replacing after around 12 years.
Usually not in England: panels on a house are permitted development as long as they project no more than 200mm from a pitched roof, or stand no more than 600mm above the highest part of a flat roof. They must not go on a building within the grounds of a listed building, and in a conservation area not on a wall that fronts a highway. The rules were updated on 27 August 2026; until 27 August 2027 you may follow either the old or the new set. That is the Planning Portal for England; elsewhere in the UK, ask your local planning authority.
Yes, says the Energy Saving Trust; they are normally tilted up and often weighted down so the roof covering stays watertight, which means the roof has to carry the weight. For permitted development in England the highest part of the equipment may be no more than 600mm above the highest part of the roof.
Yes, on a suitable frame (Energy Saving Trust). For a house in England the array may be no more than 9 square metres without a planning application. Height is limited to 2 metres within 5 metres of the boundary, 1 metre if that spot is also in front of the house, and 4 metres anywhere else (Planning Portal, rules from 27 August 2026).
There are no dedicated solar panel grants from the UK Government, says the Energy Saving Trust. In England the Warm Homes: Local Grant can include solar panels, fully paid by the council, if your household income is usually £36,000 a year or less or you qualify another way (GOV.UK). Everyone else gets the 0% VAT until 31 March 2027.
Yes. A battery is an extra of around £5,000 to £8,000 (Energy Saving Trust), and it is not in the prices on this page. Without one, what you do not use goes back to the grid at typically around 12p a unit, while you normally buy electricity for more than twice that, so using your own power first is what pays.