Plug-in solar: what it makes, and will it work in a power cut?
An 800 W plug-in solar kit in the south of England makes about 653 kWh a year: worth about £86 a year at the current price cap if you use half of it as it is made. It does not work in a power cut unless it has its own battery with a backup socket.
Plug-in (balcony) solar is a panel or two with a small inverter that plugs into an ordinary socket and feeds whatever the house is using at the time. Since 27 August 2026 it has been legal in Great Britain to plug in a kit of up to 800 W that meets the government's product specification.
How much it makes, and saves
A kit only saves money on the electricity you use while it is generating; without a battery, what you do not use flows out to the grid and usually earns you nothing. How much you use depends on whether anyone is home in the day, so the table shows three cases rather than one number. They are illustrations, not measurements.
| Kit | Where | A year | Use 30% | Use 50% | Use 70% |
|---|---|---|---|---|---|
| 400 W | London, 51.5°N | 326 kWh | £26 | £43 | £60 |
| 400 W | Glasgow, 55.9°N | 277 kWh | £22 | £36 | £51 |
| 800 W | London, 51.5°N | 653 kWh | £52 | £86 | £120 |
| 800 W | Glasgow, 55.9°N | 554 kWh | £44 | £73 | £102 |
| Kit | Where | A year | Use 30% | Use 50% | Use 70% |
|---|---|---|---|---|---|
| 400 W | Boston, 42.4°N | 444 kWh | $24 | $41 | $57 |
| 400 W | Phoenix, 33.4°N | 657 kWh | $36 | $60 | $84 |
| 800 W | Boston, 42.4°N | 888 kWh | $49 | $81 | $114 |
| 800 W | Phoenix, 33.4°N | 1,314 kWh | $72 | $121 | $169 |
Summer and winter are very different. In June the 800 W kit makes about 2.9 kWh on an average day in the south of England; in December about 0.5 kWh. For scale, a fridge-freezer uses about 1 kWh a day. The sum is panel watts × peak sun hours for the month × 75% for real-world losses, with the panels angled towards the sun; flat or shaded panels make noticeably less.
The rules
Great Britain
Regulations that came into force on 27 August 2026 allow a solar kit to plug into an ordinary socket and run alongside the grid, as long as it puts out no more than 800 W and meets the government's interim product specification. They do not cover kits designed to store electricity taken from the grid, so if a kit has a battery, check it is sold as meeting the UK rules. The regulations.
United States
There is no national rule. Utah was the first state to allow plug-in solar without a utility agreement, for kits up to 1,200 W, in 2025. Colorado passed a law in May 2026 that stops power companies requiring approval for portable-scale solar. Other states have bills in progress. Elsewhere, connecting any generator to a home's wiring normally needs the utility's permission, so check your state and your utility first. Utah HB 340, Colorado HB26-1007.
Kits with a battery
A battery lets the kit keep its daytime power for the evening, and some give you a socket that works in a power cut. These are the main ones; check the UK or US version's own specification, as the lines change quickly.
| Kit | Battery | To the house | In a power cut | Sold in |
|---|---|---|---|---|
| Anker SOLIX Solarbank 3 E2700 Pro | 2.7 kWh (to 16.12) | 800 W | Emergency socket | EU |
| Jackery SolarVault 3 Pro | 2.52 kWh (to 15.12) | 800 W | 1,200 W socket | UK |
Sources: Anker, Jackery. Read 2026-09-26.
Plug-in solar kits
With a battery
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For power cuts, a panel and a power station
If the point is keeping the lights and the fridge going when the grid is down, a portable solar panel plugged into a power station works where a plug-in kit cannot: nothing is connected to the house wiring, so nothing has to switch off. A 200 W panel in June in the south of England puts back about 0.7 kWh a day. Every power station page shows how long it takes to recharge by region and month.
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