Plug-in solar

On 27 August 2026, small "plug-in" (also called "balcony") solar panel kits became legal to sell and self-install in Great Britain for the first time - a product category already common in Germany, now permitted here under new government rules. This is the first of eight pages covering the topic in depth: what it is, safety, batteries, things to consider before fitting one, where you are allowed to mount it, how to register it, a detailed energy/savings calculator, and certification. Use the tiles below to jump straight to any of them.

A plug-in solar kit must connect directly into a wall socket. Do not use extension leads, multi-way adaptors, travel adaptors or RCD adaptors - the Interim Product Specification requires a direct plug-to-socket connection. See Extension leads for why.

What is it?

A plug-in solar kit is one or more small solar panels wired to a "microinverter" that plugs directly into an ordinary wall socket using a standard UK plug - no rewiring, no consumer unit work, and (for a suitable existing installation) no electrician required. While the panels are generating, the power feeds straight into whichever appliances in your home are switched on at that moment - a kettle, a fridge, a TV - reducing how much you import from the grid. There is no export payment mechanism for these small unmetered systems: electricity you generate but do not use at that instant flows out onto the grid the same as any small grid-tied inverter's would, but there is no metering or tariff set up to pay you anything for it, so from your point of view it is wasted - which is why how much time you spend at home during daylight hours matters as much as panel size for how much you will actually save.

This is a distinct, much smaller-scale product from a full rooftop solar PV installation (typically 3-5kW, professionally installed, MCS-certified, often paired with a battery and an export tariff). Plug-in kits are capped at a fraction of that size by design - see Certification for how the two schemes differ - and are aimed at renters, leaseholders and anyone who wants a small amount of self-generated power without a full installation.

Do not plug in more than one kit. The network rules (G98, as amended in August 2026) allow exactly one plug-in solar device per household, notified as a single unit to your network operator (see Registration for how). A second kit on another socket is not permitted, even though the product specification on its own would allow one per circuit - see Considerations and Registration for the detail.

The current rules at a glance

Plug-in solar is governed by four official documents. The DESNZ Interim Product Specification has not been updated or replaced since it was finalised - version 2, published 16 July 2026, is still current, and it is the version the law itself refers to.

  • The lawSI 2026/848, in force from 27 August 2026. It amends the Plugs and Sockets etc. (Safety) Regulations 1994 (UK-wide) and the Electricity Safety, Quality and Continuity Regulations 2002 (Great Britain only), and defines a plug-in microgenerator as a solar device with an AC output of no more than 800 watts, plugged into a standard socket
  • The product rulesPlug-in Solar Device Interim Product Specification, version 2 (DESNZ, 16 July 2026). The government says longer-term standards will be developed to succeed it, with no timeline yet - see Certification
  • The network rulesEngineering Recommendation G98, amended for plug-in solar by Ofgem's decision of 11 August 2026 and in effect since 27 August 2026: one plug-in solar device per household, and your network operator must be told when you connect or remove one - see Registration
  • Planning (England)The Town and Country Planning (General Permitted Development) (England) (Amendment) Order 2026, in force from 27 August 2026, which adds plug-in solar specifically - see Mounting
  • BatteriesNot covered. Plug-in batteries remain prohibited, and compliant kits must carry a warning not to be used with battery storage - see Battery power
  • Where it appliesGreat Britain. Northern Ireland is not covered yet - see Mounting

Sources: SI 2026/848, Interim Product Specification v2, Ofgem G98 decision, SI 2026/896. Last checked: 29 October 2026.

Why the power gets used by your home, not the grid

Your appliances do not "choose" solar power over grid power - electrically, there is nothing for them to choose between. What actually happens is simpler: your plug-in kit's inverter and the incoming grid supply both feed the same shared socket circuit that your sockets are wired to, and your electricity meter only counts whatever actually crosses it on its way in from the grid. Whatever the inverter is generating at a given moment is drawn by whatever's switched on in your home before anything needs to cross the meter at all - so it is "used first" because it never had to travel that far.

How plug-in solar power and grid power both reach your appliances The solar inverter and the grid both connect to the same socket circuit that feeds your sockets; the meter only measures what crosses from the grid side. Solar panel + inverter Grid supply (through your meter) Your home's sockets & appliances (the socket circuit) Generated power reaches appliances Grid tops up only the shortfall, via the meter

Simplified illustration: both sources feed the same socket circuit, so demand is met from whichever supply is available at that instant. The meter sits on the grid side only - it has no way to "see" what your panel is supplying, only what still has to come from the grid to make up the difference.

A worked example: if your kettle and fridge are together drawing 900W and the panel is putting out 400W at that moment, your appliances still draw 900W in total, but only the remaining 500W is pulled from the grid and shows up on your meter as import - the other 400W did not need to come from there. It works the same way in reverse: if your home is using less than the kit's output - say it is putting out its full 800W maximum but your home is only drawing 300W at that moment - the other 500W does not just disappear. Like any small grid-tied inverter, it flows out through your supply onto the wider grid. But it is not banked or paid for: there is no metering or export tariff set up for a kit like this, so that exported 500W earns you nothing - it is neither used nor rewarded. That is a separate point from anti-islanding (see Safety), which only acts if the inverter loses its connection to the grid altogether - it is not there to stop export during normal, connected operation. This is also why how much time you spend at home during daylight hours has such a big effect on your actual savings, independent of panel size or location.

How much sun does Great Britain actually get?

The single biggest factor in what a plug-in kit generates is not the kit at all - it is where in the country you are and what month it is. "Peak sun hours" is the standard way solar output is measured: one peak sun hour equals 1 kWh of solar energy per square metre, roughly what you would get from an hour of a clear midday sun. Averaged over a full year, Great Britain gets nowhere near the Sahara, but it is also not as bleak as reputation suggests - southern England receives roughly four times as much irradiance in June as it does in December, and the north-south spread across the country is about 28% at the winter low point.

JanFebMarAprMayJunJulAugSepOctNovDec

Illustrative monthly solar irradiance for London (kWh/m²/day, 20-year satellite average). Full location-by-location data, for ~20 UK towns and cities, is built into the Energy calculator.

Source: sunhours.app: UK solar hours by region (20-year, Jan 2001-Dec 2020, satellite-derived irradiance climatology). Last checked: 20 September 2026.

Sources

Rules last checked: 29 October 2026, against the Interim Product Specification v2 (16 July 2026), SI 2026/848 and Ofgem's G98 decision of 11 August 2026. The specification has not been updated or replaced since July 2026.

This page is informational, not financial or electrical-safety advice. Always check a specific kit against the live ENA register (see Certification), and get a qualified electrician's opinion if your consumer unit is old, your circuits are unidentified, or anything about your installation looks unusual, before fitting one yourself (see Considerations).