Is plug-in solar worth it? UK savings and payback calculator
It can be, if you have a sunny spot and someone is home in the day. Using the government's own figures, an 800W plug-in solar kit facing south at a 30° tilt saves about £113 a year at the October 2026 price cap, so a £500 kit pays for itself in about 4.4 years. Hung upright on a balcony facing east or west, it saves about £72 a year and takes about 7.0 years.
Plug-in solar (sometimes called balcony solar) has been legal in England, Scotland and Wales since 27 August 2026. Use the calculator to pick where your panels would go. It starts at the price cap rate of 26.32p per kWh for electricity (1 October to 31 December 2026), and you can change any figure to match your own.
Work out your saving and payback
Pick where the panels would go, then change any number to match your home. Everything updates as you type.
What it costs
These are the government's own rough cost assumptions.
- You use about 428 kWh a year of the solar power at home, and about 262 kWh goes back to the grid unpaid.
- That is about £9.38 a month on average, but much more in summer than in winter.
- Over 15 years at today's prices, you would be about £1,089 better off, after allowing £100 for a new inverter after 10 years.
A guide, not a quote. It ignores future price changes and the standing charge, which solar does not change.
Plug-in solar payback by spot and kit price
Years to pay back an 800W kit, using the government's generation and home-use figures, electricity at 26.32p per kWh and nothing paid for spare power. The government says kits are likely to cost around £400 to £600 at first. The last column adds £200 for an electrician to fit an outdoor socket.
| Where the panels go | Used at home a year | Yearly saving | £400 kit | £500 kit | £600 kit | £700 (kit + socket) |
|---|---|---|---|---|---|---|
| Facing south, tilted at about 30° | 428 kWh of 690 | £113 | 3.6 yrs | 4.4 yrs | 5.3 yrs | 6.2 yrs |
| Somewhere in between | 350 kWh of 534 | £92 | 4.3 yrs | 5.4 yrs | 6.5 yrs | 7.6 yrs |
| Upright on a wall or balcony, facing east or west | 272 kWh of 378 | £72 | 5.6 yrs | 7.0 yrs | 8.4 yrs | 9.8 yrs |
Your home will differ. These figures assume average electricity use (3,323 kWh a year), someone home on weekday daytimes, no battery and little shade. Checked 7 October 2026.
Is plug-in solar legal in the UK?
Yes, in England, Scotland and Wales, since 27 August 2026. A new law, SI 2026/848, lets a plug-in solar kit use a normal 13A plug and socket, as long as the kit meets the government's Plug-in Solar Device Interim Product Specification. The Energy Saving Trust says plug-in solar is not yet permitted in Northern Ireland.
Here are the main limits, from the law and the specification:
- The kit can feed no more than 800W into your home.
- The panels can add up to 2,000W. Above 960W, think about an electrician checking your wiring first.
- It must plug straight into a fixed wall socket with its own plug. No extension leads or adaptors.
- Only one plug-in solar kit per home for now, according to the Energy Saving Trust.
- It is solar only. Plug-in batteries are not covered by these rules.
- You must register it so your electricity network operator knows it is there.
Before you buy
The Energy Saving Trust checklist, written with the government, is the best place to start. In short:
- Check the exact model is on the ENA Connect Direct device register of UK-compliant kits.
- Get permission first if you rent, own a leasehold flat or live in a managed building.
- Check whether you need planning permission or listed building consent.
- Look at your fuse box. If it has old rewireable fuses rather than switches marked RCD, RCBO or MCB, the Energy Saving Trust says not to install plug-in solar.
- Use a socket on a circuit with no lights or wired-in appliances such as a boiler or cooker.
- An outdoor socket must be weatherproof and fitted by a qualified electrician.
- Fix the panels securely so they cannot blow over, and tell your home insurer.
How it's worked out
Electricity made. The two main spots come straight from the government's impact assessment for plug-in solar. For 800W of panels with little shade, it estimates about 690 kWh a year facing south at a 30° tilt, and about 378 kWh hung upright facing east or west. Our "somewhere in between" option is the midpoint of the two, which is also the government's central case.
Used at home. Solar only saves you money when you use the power as it is made, unless you are paid for the rest. The government assumes a home with average use and someone in on weekday daytimes uses 62% of the power from the south-facing kit and 72% from the upright one. So the south-facing kit makes about 21% of an average home's yearly electricity, but only about 13% ends up replacing power you would have bought.
Saving is the power you use at home times your electricity rate, plus anything you are paid for the rest. Payback is the up-front cost divided by the yearly saving. It is a simple guide. It ignores future price changes, and most of the saving comes between spring and autumn.
Costs. The government's model uses £500 for a kit, £150 if you pay for help with mounting, £200 for an electrician to fit an outdoor socket, and £100 for a new inverter after 10 years. We use the same figures, and you can change the kit price.
The south-facing example works out at about £113 a year at today's cap. The government's own figure, at the July to September 2026 cap, was about £110, which is why it says households could save up to £110 a year.
Common questions
Is plug-in solar worth it in the UK?
It can be, if you have a sunny spot and use power in the daytime. Using government figures at the October 2026 price cap of 26.32p per kWh, an 800W kit tilted south saves about £113 a year and pays back a £500 kit in about 4.4 years. Hung upright on a balcony facing east or west, it saves about £72 a year and takes about 7.0 years.
Is plug-in solar legal in the UK?
Yes, in England, Scotland and Wales since 27 August 2026, as long as the kit meets the government's product specification. The law (SI 2026/848) lets a compliant kit use a normal 13A plug and socket. The Energy Saving Trust says plug-in solar is not yet permitted in Northern Ireland.
How much electricity does an 800W plug-in solar kit make?
Government modelling puts it at about 690 kWh a year for 800W of panels facing south at a 30° tilt with little shade, and about 378 kWh a year hung upright facing east or west. The government says that is up to 20% of an average home's electricity use. Shade, a poor angle or a cloudier area will mean less.
What is the maximum size of plug-in solar allowed?
The inverter can feed no more than 800W into your socket. The panels themselves can add up to 2,000W, and the inverter caps the output at 800W. If your panels add up to more than 960W, the specification says you should think about having an electrician check your wiring first.
Can I use an extension lead?
No. The kit must plug straight into a fixed wall socket using the plug it came with. Extension leads, multi-way adaptors, travel adaptors and RCD adaptors are not allowed. The Energy Saving Trust also says to use a socket on a circuit that does not power lights or wired-in appliances like a boiler or cooker.
Do I need to register plug-in solar?
Yes. You need to tell your electricity network operator when you install it and when you remove it. The Energy Saving Trust says registering is a legal requirement and points to the UK plug-in solar registration website, which asks for your name, postcode and the make and model of the kit.
Will I get paid for the electricity I send back to the grid?
Probably not at first. Export payments under the Smart Export Guarantee normally need a certified installation and a meter that records exports, and the government expects that this will not apply to many plug-in solar owners to begin with. That is why the calculator starts the export rate at 0p.
Can I fit plug-in solar if I rent or live in a flat?
Only with permission. Get the go-ahead from your landlord, freeholder or building manager before you buy, especially if you need to drill or fit an outdoor socket. Flats, buildings with cladding and timber balconies can have extra fire safety rules. You may also need planning permission or listed building consent.
How do I get the most from plug-in solar?
Pick an unshaded, south-facing spot and tilt the panels if you can. Then use more electricity while the sun is out, for example running the washing machine or dishwasher in the middle of the day. An energy monitor plug on your appliances shows what they use, so you can see what the panels could cover. Never put one between the solar kit and the wall, as the kit must plug straight into the socket.
How long does a plug-in solar kit last?
The government's cost model assumes you may need a new inverter after 10 years, at about £100, and looks at costs and savings over 15 years. It calls the 10-year figure cautious and expects many kits to last longer. Check the warranty on the kit you buy.
See what your appliances use
Solar pays back fastest when you use the power in the daytime. An energy monitor plug shows what your fridge, washing machine or heater really uses, and our heater running cost calculator shows what an electric heater costs per hour. Use the monitor plug on appliances only. The solar kit itself must go straight into the wall socket.
Sources
- The Plugs and Sockets etc. (Safety) Regulations 1994 and Electricity Safety, Quality and Continuity Regulations 2002 (Amendment) Regulations 2026 (SI 2026/848). Legal from 27 August 2026; 800W maximum output; must meet the product specification.
- DESNZ, Plug-in Solar Device Interim Product Specification, version 2 (July 2026). 2,000W panel limit, 960W electrician advice, no extension leads or adaptors, register with the network operator.
- DESNZ, Plug-in solar: final stage impact assessment (July 2026). Generation, home-use share and cost assumptions (Table 7 and paragraphs 24 to 25).
- GOV.UK news, Households can save as plug-in solar panels come to market (26 August 2026). Up to £110 a year and up to 20% of an average home's electricity.
- Energy Saving Trust, Plug-in solar panels: checks to make before you buy. Permissions, socket and fuse box checks, one kit per home, registration, Northern Ireland.
- Ofgem decision on DCRP/MP/26/02, plug-in microgeneration (August 2026). Network operator notification.
- Ofgem, Energy price cap unit rates and standing charges. Electricity 26.32p per kWh, average Direct Debit rate for England, Scotland and Wales (1 October to 31 December 2026).
Figures checked 7 October 2026. This is general information, not electrical or legal advice.