Solar Panel Cost Calculator: See What Solar Would Cost and Save on Your Roof
Answer eight questions about your home. We show the installed cost, the yearly saving, the payback years and an honest verdict, with the working.
Your solar cost, savings and payback
Updates as you answerExample: 9 panels of 475 W, a 4.275 kWp system. Your answers change the saving and the payback. Tell us how many panels fit your roof to change the size.
The system pays back in about 12.8 years. That is longer than our Good fit range and inside our Borderline range.
Get a free survey from MCS-registered installers. The request form is not open yet.
VAT on home solar panels and batteries is 0% until 31 March 2027. From 1 April 2027 it is 5%. Our estimate with 5% VAT would then be £8,800.
- Example system size
- 4.275 kWp
- Panels
- 9 of 475 W
- Panels to match your yearly use
- 6 panels
- Yearly use (the Ofgem typical value)
- 2,500 kWh
- Yearly generation
- 4,138 kWh
- Used at home
- 21%
- A typical home in our data uses
- 23%
- Export income
- £423.54
- 25-year net
- £6,232.92
- Cost from 1 April 2027, with 5% VAT
- £8,800
- Rate for electricity you use
- 26.32p per kWh
- Rate for electricity you export
- 13p per kWh
Yearly generation basis: a stand-in figure of 968 kWh per kWp for a south roof at 35 degrees, because no postcode area in our table is set. Type your full postcode and the figure for your area is used.
Installed cost basis: the mean cost per kWp of panels fitted (total installed capacity), from DESNZ Solar PV cost data, domestic retrofit installations, 1 April 2025 to 31 March 2026.
Used at home basis: a cautious figure. Three in four of the homes like yours in our data used at least this share of their solar electricity. The saving, the export income, the payback and the verdict are worked from it.
Rates basis: the unit rate is the Ofgem price cap for October to December 2026. The export rate is our calculation from Ofgem figures.
- For information: a system of this size may need an inverter above 3.68 kW per phase. That is the limit, on a single-phase supply, for the simpler grid notice (G98). Above it the network operator must approve the connection before fitting. The limit is about the inverter, not the panels, and we do not know your inverter. The installer sends the notice to the network operator.
How our calculator works. Sources and data dates.
Solar generation data: PVGIS © European Communities, 2001-2026.
How we worked this out
- Generation = kWp x yield factor x shade factor
- Saving = self-consumed kWh x unit rate
- Export = exported kWh x export rate
- Payback = cost / yearly benefit
How Much Do Solar Panels Cost in the UK?
Solar panels cost about £8,400 fitted for a 4 kWp system, at 0% VAT, based on the DESNZ Solar PV cost data mean for home retrofit installations, April 2025 to March 2026.
A kWp, or kilowatt peak, is the rated output of the panels. 4 kWp is one size in our table, not a typical size: on panel capacity, 46.6% of home systems fitted in 2025/26 were up to 4 kW and 48.3% were 4 to 10 kW. Our guide to solar panel cost in the UK gives the full figures by size, house and nation.
The table prices seven sizes the way the calculator does. The same sum for 13 sizes, with panels and output, is on our page on solar panel cost by system size.
| System size | Installed cost | DESNZ mean per kWp for the size band | Extra VAT at 5% from 1 April 2027 |
|---|---|---|---|
| 2 kWp | £4,200 | £2,109 | £210 |
| 3 kWp | £6,300 | £2,109 | £315 |
| 4 kWp | £8,400 | £2,109 | £420 |
| 5 kWp | £8,400 | Priced as 4 kWp (our rule) | £420 |
| 6 kWp | £9,900 | £1,651 | £495 |
| 8 kWp | £13,200 | £1,651 | £660 |
| 10 kWp | £16,500 | £1,651 | £825 |
Four things move a quote away from these figures. Size comes first: the total rises with size, apart from 4 to 5 kWp, which share one price under our rule, while the cost per kWp is lower in the larger band. Your roof is next: our estimate leaves out scaffolding, roof work and wiring extras, and a survey prices them. What the quote includes matters too: the DESNZ figure counts the equipment, the installation, the connection to the supply and any VAT, and leaves out batteries, extended warranties and other works. Region is the last: for installs up to 4 kW, the DESNZ mean across all installations ran from £1,878.20 a kW in the North East to £2,176.96 in London. The calculator uses one Great Britain figure for every postcode.
Your household's electricity use changes what solar saves, not what it costs. Your house size and your nation come next.
Solar Panel Cost by House Size and Nation
Solar panel cost follows system size, not bedrooms, so the calculator prices a home of any size on its labelled example of 9 panels of 475 W (4.275 kWp), about £8,400, until you say how many panels fit your roof. Our page on solar panel cost by house size covers the house-by-house detail.
Bedrooms change the yearly use the calculator assumes, and through it the saving. The table gives the DESNZ figure it uses for each bedroom count.
| Bedrooms | Median yearly use |
|---|---|
| 1 | 1,666 kWh |
| 2 | 2,137 kWh |
| 3 | 2,659 kWh |
| 4 | 3,371 kWh |
| 5 or more | 4,581 kWh |
Your own figures beat a bedroom count: type your yearly use or your monthly bill, and the calculator uses that instead. The second table compares the cost per kW by nation.
| Nation | Up to 4 kW | 4 to 10 kW |
|---|---|---|
| England (our calculation) | £2,042 | £1,795 |
| Scotland | £1,944 | £1,662 |
| Wales | £1,951 | £1,641 |
| Northern Ireland | Not in the DESNZ data | Not in the DESNZ data |
Your estimate uses the calculator figure, and the size behind it is the next question.
How Many Solar Panels Do You Need for Your Home?
A home using 2,500 kWh of electricity a year needs about 6 panels, a system of about 2.58 kWp, at 475 W a panel on a south roof at 35 degrees with no shade, at our stand-in yield for a home with no postcode given.
That is the rule our tool for how many solar panels you need uses: it sizes the panels to your yearly kWh use, then checks what fits your roof. kWp is the panels' rated output in full sun, and kWh, a kilowatt-hour, is the unit on your bill.
System size (kWp) = yearly use (kWh) ÷ yearly output per kWp for your roof; panels = kWp × 1,000 ÷ panel watts, rounded up
Three things set the answer: your yearly use, the yield, which is what each kWp generates in a year on your roof, and your roof space. The smaller number is the size when your roof takes fewer panels than your use calls for. Higher-wattage panels reach the same kWp with fewer panels.
The calculator at the top of this page sizes the system another way. It opens on a labelled example of 9 panels of 475 W (4.275 kWp) and stays on it until you say how many panels fit your roof; then it prices that many. Your yearly use, bedrooms and daytime occupancy still change the saving, the payback and the verdict, but not the size. For comparison, the result also shows the panels that would generate your yearly use.
Adding a battery to those panels changes the cost, and that comes next.
Solar Panels With a Battery: Cost, Size and When It Pays
A home battery costs about £6,500 for 5 kWh to about £12,600 for 20 kWh fitted, on the DESNZ median price per kWh for batteries in existing homes, April 2025 to March 2026. With the calculator's labelled example of 9 panels of 475 W (4.275 kWp), panels and a 5 kWh battery cost about £14,900.
A battery is sized in kWh, the energy it stores, and the size here is the one on the label. A 10 kWh battery costs about £8,900, and 13.5 kWh and 15 kWh both cost about £9,800, because the calculator never prices a bigger battery below the top of the band beneath it. That is our rule, not a DESNZ figure.
Our solar battery cost calculator works out the price and the payback of the battery size you pick, on its own or with panels. The table compares the two for the calculator's default home.
| Measure | Panels only | With a 5 kWh battery | With a 10 kWh battery |
|---|---|---|---|
| Installed cost | £8,400 | £14,900 | £17,300 |
| Share of solar used at home | 22% | 46% | 50% |
| Payback | 13.6 years | 20.6 years | 23.2 years |
Every battery size on the form comes out as a Poor fit for the calculator's default home today, on DESNZ prices. A battery raises the share of solar power you use at home, but the saving it adds does not repay its price within our payback limits. Prices for other sizes of panels with a battery are in our guide to solar panels and battery cost.
A time-of-use tariff, one with cheaper electricity at set hours, lets a battery charge from the grid at night. Some carry conditions: Octopus Go needs an electric car charged at home, and Cosy Octopus needs a heat pump, electric radiator or electric boiler (Octopus Energy, read on 11 November 2026). The battery calculator adds cheap-rate charging when you type a day and a night rate. The calculator on this page does not model time-of-use charging.
Whether panels alone are worth it is the bigger question.
Are Solar Panels Worth It for Your Home?
Solar panels pay back in about 13.6 years with export income for a home like the calculator's default one, on our estimate. That home has a 4 kWp system at £8,400 and uses 2,500 kWh a year. It has someone home some days and a south roof at 35 degrees with no shade, and pays 26.32p per kWh, with 13p per kWh for export.
As an example result, the calculator gives its default home a Borderline verdict. Worth it means you compare two things: what the panels cost to fit, and what they save and earn each year. The verdict makes that comparison for your own answers, and our page that asks are solar panels worth it explains the reasoning behind it.
Each verdict, and what decides it, is in the table below.
| Verdict | What gives it | What the result offers next |
|---|---|---|
| Good fit | A payback of 10 years or less, on a roof that is not north-facing or heavily shaded | The survey step for an owner; a tenant is asked to share the estimate with the landlord |
| Borderline | A payback longer than 10 years and up to 15 years | The survey step for an owner; a tenant is asked to share the estimate with the landlord |
| Poor fit | A north-facing roof, heavy shade, no yearly saving, or a payback longer than 15 years | What would change the answer, and run it again; no survey |
On a north-facing roof the calculator returns a Poor fit whatever your other answers, and heavy shade does the same. In our PVGIS calculation a north roof at 35 degrees makes 54.2% of the output of a south roof at the same pitch, against 79.5% for an east roof. On an east or west slope the calculator works the verdict out from the payback instead.
Your own answers move the payback. Your postcode area sets the yield from our PVGIS run, the roof direction, pitch and shade cut or keep it, and someone at home in the day uses more of the power. If an installer has already quoted you, type the total in the optional "Have a quote?" box. The calculator then works the payback and the verdict from your price, with its own figure shown beside it. The result also shows a 25-year net figure: what the system saves and earns over 25 years, less its cost and one inverter replacement. That sum lets output fall a little each year and holds prices flat.
Two things the calculator does not ask also decide the answer. Moving out before the payback year leaves you with less saving than the system cost. A roof that needs replacing soon means the panels have to come off and go back on. Weigh both before you decide.
Our guide to the solar panel payback period works through, step by step, how many years the savings take to cover the cost. The yearly saving is one half of that sum.
How Much Will Solar Panels Save on Your Electricity Bill?
Solar panels save about £227.93 a year on your electricity bill in the calculator's default home with 4 kWp of panels, plus about £390.78 a year in export income, at the Ofgem price cap unit rate of 26.32p per kWh for 1 October to 31 December 2026.
Self-consumption is the solar power you use at home, and each kWh saves the full unit rate. Export is the rest, sent to the grid, and each kWh earns the lower export rate of 13p.
The calculator headlines a cautious share used at home, 21% for the default home on its labelled example of 9 panels of 475 W (4.275 kWp): the 25th percentile of the homes in its group, from the measured half-hourly use of London homes. The middle home of that group, the typical home in our data, uses 23%, and the result card shows that figure beside the cautious one. We headline the cautious figure because our model gives a higher share than the MCS MGD 003 figures we checked it against. So treat the saving as likely to be on the generous side.
The calculator uses your own unit rate when you type one. A monthly bill works too: the calculator turns it into yearly kWh from the unit rate and the standing charge. The standing charge of 54.83p a day stays whatever the panels generate. Export is the other half of the benefit.
Export Income: The Smart Export Guarantee and Export Tariffs
Installations on Smart Export Guarantee tariffs were paid about 13p per kWh on average from April 2024 to March 2025, our calculation from Ofgem figures (£56.97 million paid for 443.1 GWh exported). The calculator uses that export rate, and the result shows export income as its own line beside the bill saving.
The Smart Export Guarantee (SEG) started on 1 January 2020. It is not the Feed-in Tariff, which closed to new applicants on 1 April 2019. Suppliers with 150,000 or more home electricity customers must offer at least one SEG tariff.
Each kWh you export earns a payment, and our hub on the Smart Export Guarantee explains who pays and what you need. For solar up to 50 kW, the installation and the installer must be MCS certified or equivalent. You also need an export meter that can take half-hourly readings, with an export MPAN. The SEG applies in Great Britain only; in Northern Ireland the calculator uses the Power NI export rate of 11.88p per kWh.
Export tariffs differ by supplier, and some carry a condition. Three from one supplier are in the table as examples.
| Tariff | Rate | Condition |
|---|---|---|
| Next Flex Export v1 | 6p per kWh | Variable; no import condition listed; an MCS or Flexi-Orb certificate and a smart export meter |
| Next Export Exclusive v3 | 13p per kWh | Fixed for 12 months; needs an E.ON Next import tariff that is not a time-of-use tariff; systems up to 15 kW |
| Next Export Premium v3 | 17.5p per kWh | Fixed for 12 months; needs a solar or battery installation by E.ON Installation Services from 10 November 2025; systems up to 15 kW; a smart export meter; one tariff per property |
The calculator uses your own export tariff rate when you type one. The price of the panels has one dated change ahead: VAT.
0% VAT on Solar Panels Ends on 31 March 2027
VAT on home solar panels and batteries is 0% until 31 March 2027 and 5% from 1 April 2027 (HMRC VAT Notice 708/6).
On a 4 kWp system, the price is £8,400 today and about £8,800 from 1 April 2027. The VAT step is £420, which is 5% of the £8,400 price and is not rounded; the calculator rounds the 5% price to the nearest £100.
The result card carries a dated VAT note. Our page on VAT on solar panels explains which rate applies to a job that runs close to the change. A battery fitted on its own, or added to panels you already have, has been in the same relief since 1 February 2024. The 0% rate covers the whole UK, and in Northern Ireland it has applied since 1 May 2023. The calculator adds no VAT to a price you type in the "Have a quote?" box, so ask the installer which rate the quote includes.
The Warm Homes Loan Scheme is a loan, not a grant or a tax relief. Live since 27 October 2026, it covers up to £15,000 for solar panels and up to £15,000 for a battery, fitted by an MCS-certified installer, for households across the UK. Owner-occupiers and private landlords borrow from a participating lender, which runs its own credit and affordability checks, and some loans are interest free. Our page on the Warm Homes Loan Scheme has the detail. We explain loans and do not arrange them.
A loan is repaid and a grant is not. Grants are the next question.
Can You Get Solar Panels Through a Grant?
We found no grant for solar panels that covers the whole UK. Each nation runs its own schemes, and each scheme sets its own tests, such as household income, benefits and the home's energy rating. The scheme, not this page, decides whether you qualify.
Our hub on solar panel grants sets out every scheme that could cut the cost. The table gives the main route in each nation.
| Nation | Scheme | Who it is for | Solar panels |
|---|---|---|---|
| England | Warm Homes: Local Grant, until 31 March 2028 | Owner-occupiers and private tenants with a gross household income usually of £36,000 or less, a means-tested benefit, or a postcode in income deciles 1 to 2, in a home rated EPC D to G | Included; a battery only alongside solar panels |
| Scotland | Home Energy Scotland Grant and Loan | Homeowners in their only or main home | No grant for solar panels; an interest-free loan of up to £5,000 for solar thermal or hybrid solar PV-T only |
| Wales | Nest, a Welsh Government scheme | Owners and private tenants with a means-tested benefit or a household income under the Nest limit, in a home rated EPC E (54) or less, or D (68) or less with an eligible health condition | Can be included at no cost, where the whole-house assessment chooses them |
| Northern Ireland | No open scheme for homeowners | The NISEP Priority PV Scheme is for Housing Executive tenants in homes the Housing Executive selects | The owner-occupier scheme, Toasty Homes, is marked closed |
Under Warm Homes: Local Grant, an owner-occupier who qualifies pays no contribution towards the work. In Scotland, Warmer Homes Scotland, a separate scheme, installed 957 solar PV or battery storage measures in 2024 to 2025, though its mygov.scot page does not name solar. For Nest in Wales, look up your home's EPC rating on the gov.uk "Find an energy certificate" service.
ECO4, the energy supplier scheme in Great Britain, closes to new measures on 31 December 2026. Our page on ECO4 and solar covers what that means for a home that hoped to use it.
The calculator shows the cost without a grant, and 0% VAT applies until 31 March 2027 whatever your income. For an owner who pays for the panels, a Good fit or Borderline result leads to the survey step.
Get a Free Survey From MCS-Registered Installers
A survey turns our estimate into a quote: we give the estimate, Leads 2 Trade arranges the survey, and MCS-registered installers give the quote after they visit your roof.
The survey request form on this site is not open yet, so we refer nobody today.
You will get phone calls. That is how surveys are arranged. Our page on how to get a free survey from MCS-registered installers says what each step involves.
The survey costs you nothing, and the calculator asks for no name, email or phone number. We are paid by Leads 2 Trade Limited when a homeowner we refer asks for a survey. You are never charged. It does not change our figures.
The calculator does not offer a survey in two cases. A tenant is told that no survey is offered and is asked to share the estimate with the landlord. A Poor fit verdict shows what would change the answer and lets you run it again.
Our figure is an estimate from dated public data, not a quote. A survey price can differ because of scaffolding, roof work or wiring, which the estimate leaves out. Once you hold a quote, our solar quote checker sets its price beside our estimate for the same system, with the difference in pounds. Our pages on what happens after you ask for a survey and on how we make money give the detail.
Every figure in the estimate comes from the method below.
How We Work Out Your Estimate
We work out your estimate on dated public data, and four of its sums are below. We estimate what solar panels and a battery would cost and save on your roof, show the working, and tell you when solar is a poor fit.
- Generation = system size (kWp) × yearly output per kWp for your postcode area, roof direction and pitch × a shade factor.
- Saving = kWh used at home × your unit rate.
- Export income = kWh exported × the export rate.
- Payback = installed cost ÷ (saving + export income).
Each input and its dated source:
- Cost: DESNZ Solar PV cost data, published 28 May 2026, the domestic retrofit mean per kWp of panels for April 2025 to March 2026: £2,109 up to 4 kWp, from 60,713 installations, and £1,651 above 4 to 10 kWp, from 81,582. Batteries: the DESNZ battery statistics, median per kWh on the label.
- Yield: our PVGIS 5.3 run for 121 postcode areas, 11 November 2026. PVGIS © European Communities, 2001-2026. Contains OS data © Crown copyright and database right 2026. Contains Royal Mail data © Royal Mail copyright and database right 2026. Contains National Statistics data © Crown copyright and database right 2026.
- Rates: the Ofgem price cap, 26.32p per kWh for 1 October to 31 December 2026; export at 13p, our calculation from the Ofgem SEG Year 5 report, published 5 December 2025.
- Use: the Ofgem typical 2,500 kWh a year from 1 July 2026, or the DESNZ NEED median for your bedrooms.
- Self-use: the measured half-hourly use of homes in Greater London, 2013. Contains data from SmartMeter Energy Consumption Data in London Households, UK Power Networks (Low Carbon London), London Datastore, licensed under CC BY 4.0. The data was cleaned, grouped and summarised by us.
The method is version 1.0. It does not model time-of-use charging, electric cars, heat pumps or scaffolding and roof extras, and it shows one figure, not a price range, because DESNZ publishes one mean for home retrofits. Our methodology, sources and changelog pages give the full detail.
Solar Water Heating: The Other Solar Option
Solar water heating is the other solar option for a home: roof collectors heat your hot water instead of making electricity. The Energy Saving Trust puts a typical system at about £5,300 fitted (updated 26 October 2026). It covers about half of a home's hot water over a year, around 90% in summer and around 25% in winter.
A system needs a hot water cylinder and about 5 m² of roof in direct sun for most of the day, facing south or between east and west, not north. Our calculator does not model solar thermal systems, and our guide to solar water heating gives the savings by fuel.
Plug-In Solar Panels vs a Rooftop System
A plug-in solar kit is limited to 800 W of output, against 4 kWp for the calculator's roof example, and costs from around £450 (Energy Saving Trust, 1 October 2026). Plug-in solar has been legal in Great Britain since 27 August 2026, one device per home; Northern Ireland does not permit it yet.
This page's calculator prices rooftop systems only, fitted by an installer. A plug-in kit goes into a wall socket, and no installer is needed. The table sets one kit beside the 4 kWp roof example.
| System | Upfront cost | Electricity a year | Bill saving a year |
|---|---|---|---|
| Plug-in kit, 800 W | From around £450 | Around 700 kWh | About £70 to £100 |
| Rooftop, 4 kWp system | £8,400 | 3,872 kWh | About £227.93 |
Export from a kit is not normally paid for, the Energy Saving Trust says. The rules are in our guide to plug-in solar panels.
How Solar Panels Work and What Is in a Home System
A home solar PV system turns daylight into electricity with panels, an inverter, the wiring and a meter, plus a battery if you add one.
PV is short for photovoltaic: light makes a solar cell "release electrons and produce an electric charge" (National Grid, last updated September 2026). The inverter turns the panels' direct current (DC) into the alternating current (AC) your home uses; power you do not use goes to a home battery or the grid.
A roof facing away from the sun, or in shade, gets less light and generates less. Our guides to how solar panels work and what solar PV is take each part in turn.
Is Your Roof Suitable for Solar Panels?
A roof suits solar panels when it faces the sun and avoids heavy shade, and its age and any permissions it needs count too. In the calculator, a north-facing roof or heavy shade alone gives a Poor fit, while a south roof at 25 degrees still makes 97.8% of its output at 35 degrees (our PVGIS calculation).
The Energy Saving Trust says most home systems are permitted development, apart from listed buildings, conservation areas and national parks, and advises checking with your local planning office. Our guide covers roof age too, for anyone asking is my roof suitable for solar.
How Long Do Solar Panels Last?
Solar panels should last 25 years or more, the Energy Saving Trust says (last updated 1 October 2026), and their output falls a little each year (degradation).
DESNZ's Home Energy Model paper says degradation rates "can vary from 0.1% to 1.1% per year" (January 2026). The calculator's 25-year net assumes 0.5% a year, our figure inside that range. It also counts one inverter replacement at £800, and the Energy Saving Trust says inverters "typically need to be replaced every 10 to 15 years". For warranties, see our guide to how long solar panels last.
Solar Panels From Your Energy Supplier
Several energy suppliers sell fitted solar panels. To check an offer, set its total, or its price per kWp, beside our figure for the same size. Our panel figure leaves out batteries, so add the same battery in the calculator when an offer includes one. Our page of energy supplier solar offers compared dates every price it shows.
Solar Panels for a Business
Solar panels for a business carry different prices and VAT, and our calculator is for homes only: 1 to 10 kWp, priced on the DESNZ mean for home retrofits. Business premises pay VAT on solar at the standard rate of 20%, because the energy-saving materials relief does not cover them (HMRC VAT Notice 708/6). The business figures are in our guide to commercial solar panel cost.
More Solar Calculators
Each calculator below takes one part of the estimate further, and the page with all our solar calculators says what each asks for.
- Solar Panel Payback Calculator
- Solar Output Calculator
- Solar Roof Checker
- How Many Solar Panels Do I Need (panel count)
- Solar Battery Cost Calculator
- Solar Quote Checker
Solar Panel Questions
What is the typical cost of installing solar panels in the UK?
About £8,400 fitted for the calculator's labelled example of 9 panels of 475 W (4.275 kWp), at 0% VAT, on the DESNZ Solar PV cost data mean for home retrofits, April 2025 to March 2026. That size is our example, not a typical size.
Do solar panels work on a north-facing roof?
Yes, with less output. A north roof at 35 degrees makes 54.2% of a south roof's output in our PVGIS calculation, so the calculator gives it a Poor fit. On an east or west slope the calculator works the verdict out from the payback instead.
Is the estimate a quote?
No. Our figure is an estimate worked from dated public data. Installers give a quote after a survey, and a survey price can differ because of scaffolding, roof work or wiring. Our disclaimer page explains the difference.
Will I get phone calls if I ask for a survey?
Yes. You will get phone calls. That is how surveys are arranged. Leads 2 Trade calls you first, then local MCS-registered installers call to arrange a visit. The survey request form on this site is not open yet.
Do I need a battery to benefit from solar panels?
No. Panels alone cut your bill and can earn export income. On DESNZ prices, every battery size on our form is a Poor fit for the calculator's default home today. Run the calculator both ways and compare the payback.
Why is the calculator free to use?
Leads 2 Trade pays us, not you. We are paid by Leads 2 Trade Limited when a homeowner we refer asks for a survey. You are never charged. It does not change our figures.
Sources
- Department for Energy Security and Net Zero, Solar PV cost data. Published 28 May 2026, for April 2025 to March 2026: the domestic retrofit mean cost per kWp by size band and its samples, the share of home systems in each band, the regional means by nation, and what the cost covers.
- Department for Energy Security and Net Zero, MCS certified domestic battery installation statistics. Last updated 28 May 2026: the median battery price per kWh of nominal capacity by size band, April 2025 to March 2026.
- Department for Energy Security and Net Zero, NEED consumption data tables 2026. Published 11 June 2026: median yearly electricity use by number of bedrooms, England and Wales, February 2024 to January 2025.
- Ofgem, Energy price cap unit rates and standing charges. The unit rate and standing charge for 1 October to 31 December 2026.
- Ofgem, Energy price cap (default tariff) update from 1 July 2026. The typical medium yearly electricity use.
- Ofgem, Smart Export Guarantee (SEG) Annual Report, SEG Year 5. Published 5 December 2025, for 1 April 2024 to 31 March 2025: the total paid and the total exported, from which we calculate the export rate.
- Ofgem, SEG: Guidance for Generators, and the Smart Export Guarantee and Feed-in Tariff pages. The SEG start date, the supplier rule, the MCS rule, Great Britain only, and the Feed-in Tariff closing date.
- Power NI, Tariff rates (renewables microgeneration). Read 8 November 2026: the export rate for 1 October 2026 to 30 September 2027.
- E.ON Next, Smart Export Guarantee (SEG) scheme. Read 11 November 2026: three export tariffs and their conditions.
- Octopus Energy, Octopus Go and Cosy Octopus pages. Read 11 November 2026: who each tariff is for.
- HM Revenue and Customs, Energy-saving materials and heating equipment (VAT Notice 708/6). The 0% rate to 31 March 2027, the rate from 1 April 2027, and the standard rate for business premises, which the relief does not cover.
- gov.uk, Announcement of 11 January 2024 on VAT relief for batteries. Batteries, on their own or added to solar panels, in the 0% relief from 1 February 2024.
- gov.uk, Warm Homes Loan Scheme: factsheet. Published 27 October 2026: start date, loan caps, borrowers, lender checks and the MCS rule.
- Department for Energy Security and Net Zero, Warm Homes: Local Grant policy guidance. July 2026: who can apply, the income routes, the EPC test and the end date.
- Home Energy Scotland, Home Energy Scotland Grant and Loan. Checked 8 November 2026: what the scheme offers for solar.
- Welsh Government, Get free home energy efficiency improvements from Nest. Checked 8 November 2026: who is eligible and what Nest can fund.
- NISEP and nidirect, NISEP list of schemes, April 2026 to March 2027, and Energy saving grants in your area. The schemes open to homes in Northern Ireland.
- Department for Energy Security and Net Zero, Extending the ECO4 end date: government response. Published 23 January 2026: the date ECO4 closes to new measures.
- European Commission Joint Research Centre, PVGIS 5.3. Yearly output per kWp for each postcode area and each roof direction and pitch (our calculation).
- UK Power Networks (Low Carbon London), London Datastore, SmartMeter Energy Consumption Data in London Households. Licensed under CC BY 4.0: the measured half-hourly use behind our self-use figures.
- Energy Saving Trust, Solar water heating. Last updated 26 October 2026: the typical installed cost, the share of hot water covered, and the roof and cylinder a system needs.
- Energy Saving Trust, Plug-in solar panels. Last updated 1 October 2026: the kit price, the yearly output and saving with their assumptions, export payments and Northern Ireland.
- legislation.gov.uk, The Plugs and Sockets etc. (Safety) Regulations 1994 and Electricity Safety, Quality and Continuity Regulations 2002 (Amendment) Regulations 2026 (SI 2026/848). In force 27 August 2026: plug-in solar devices in Great Britain.
- Department for Energy Security and Net Zero, Plug-in Solar: government response. July 2026: the 800 W limit and one device per home.
- National Grid, How does solar power work?. Energy Explained, last updated September 2026: how a solar cell makes electricity, and DC to AC.
- Energy Saving Trust, Solar panels. Last updated 1 October 2026: how long panels last, and the planning exceptions.
- Energy Saving Trust, How to clean and maintain solar panels. Last updated 1 October 2026: when inverters need replacing.
- Department for Energy Security and Net Zero, HEM-TP-18 v3.0, Modelling PV electricity generation and calculating self-consumption. January 2026: the range of yearly degradation rates.