Last reviewed: 4 September 2026. Figures and legal points checked against primary sources (legislation.gov.uk, gov.uk, Ofgem and the relevant network operator).
Last reviewed: 3 September 2026. Every figure on this page
is taken from the statutory instrument, the government’s Interim Product Specification or the DESNZ
impact assessment, each of which is linked below. Where a number comes from our own reading rather
than a government document, we say so.
Plug-in solar is a small solar system you install yourself and plug into an ordinary
socket. One or two panels feed a microinverter; the microinverter turns their output into 230 V mains
and pushes it into the circuit it is plugged into. Your appliances use that electricity before they
use anything from the grid, so your meter records less import. In Great Britain it became lawful to
use on 27 August 2026, with hard limits: 800 VA of AC output, 2,000 W of panel behind
it, and no battery. The government’s own modelling puts the saving at roughly £70 to
£110 a year depending on how you mount it.
The parts, and what each one does
A compliant kit is defined in the Interim Product Specification as at least four things: one or
more PV modules, a grid-following inverter, a connection lead fitted with a BS 1363 plug, and a
mounting system for the panel. That is the whole product. There is no isolator, no consumer-unit
work, no roof penetration and no commissioning certificate.
- The panel or panels. Typically mounted on a balcony rail, a fence, a flat garage
roof, a shed or a free-standing frame on the ground. - The microinverter. A grid-following device: it only produces power while it can
see the mains. Unplug it, or lose the grid, and it stops. That is why plug-in solar gives you nothing
in a power cut. - The lead and plug. A non-rewireable moulded plug with a BS 1362 fuse rated no
more than 5 A. You must use the manufacturer’s own lead. - The mounting kit. The specification requires that any attachment method be
reversible and non-permanent, and that it must not compromise the structural integrity, fire
performance or weatherproofing of the building.
The four numbers that define a compliant kit
This is the part most product pages get wrong, because two of the four limits are not in the law at
all — they are in the specification the law points to. The distinction matters if you ever have to
argue about it.
| Limit | The figure | Where it is written | What it means for you |
|---|---|---|---|
| AC output | Maximum rated AC output not exceeding 800 watts; the specification expresses the same ceiling as 800 VA apparent power |
SI 2026/848, in the definition of “plug-in microgenerator” | A hard legal ceiling. A 1,000 W kit is not a plug-in microgenerator and is not covered |
| Current into the socket | Maximum 3.5 A | Interim Product Specification, clause 4.1 — not in the SI | Well inside a 13 A socket’s rating; it is the reason the plug fuse is small |
| Panel capacity (DC) | Sum of PV module maximum power not exceeding 2,000 W | Interim Product Specification, clause 4.1 — not in the SI | You may legitimately oversize the panels behind an 800 VA inverter |
| Storage | None. The device must not be designed to import electricity in order to store it for later supply |
SI 2026/848, definition, limb (e) | Battery-integrated balcony kits sold in the EU are outside the framework |
There is a fifth number that almost nobody mentions: 960 W. The specification says
manufacturers must advise consumers whose total PV module capacity is above 960 W to consider a
professional assessment of their existing electrical installation first. It is advice, not a ban — but
it is in the document, and it is a fair warning if you are planning a four-panel array.
What it will actually save you
DESNZ published two worked examples in the impact assessment that accompanied the regulations. Both
assume 800 W of panel, a Great Britain average household using 3,323 kWh a year, a “home all day”
occupancy pattern, average irradiance and little or no shading. Crucially, the savings are calculated
only from electricity consumed on site: exported units are valued at nothing.
| Mounting | Self-consumption rate | kWh used at home | DESNZ annual saving |
Our note |
|---|---|---|---|---|
| 30° tilt, facing south | 62% | 428 | about £110 | The best case: a frame in a garden or on a flat roof, not a balcony rail |
| 90° tilt (vertical), facing east or west | 72% | 272 | about £70 | The typical balcony install. Generates less, but a higher share of it is used |
Two things fall out of that table and neither is intuitive. First, the vertical east/west case has
the higher self-consumption rate, because its output is spread across morning and afternoon
rather than piling up at midday when nobody is in. Second, the gap between the two is smaller than the
gap in raw generation — 690 kWh against 378 kWh — which tells you that with no export payment, what
matters is not how much you make but how much you happen to be using at the time. Our
savings calculator lets you change the
occupancy and orientation assumptions; the reasoning is set out in
plug-in solar savings and payback.
What plug-in solar is not
- It is not rooftop solar in miniature. A conventional 4 kWp roof array is roughly
five times the capacity, is certified under MCS and earns export payments. A plug-in kit is none of
those things. - It does not earn you export payments. The Smart Export Guarantee requires MCS
certification or an accepted equivalent and an export meter point. A self-installed kit has neither,
and DESNZ’s own impact assessment says the SEG “is likely not to apply in the first instance for many
plug-in solar installers”. See
SEG and plug-in solar. - It is not a backup supply. Grid-following inverters shut down when the grid does.
- It cannot be paired with a battery. The specification requires a prominent
warning that the device is not intended to be used with a battery energy storage system. If storage
is what you want, that is a separate, hard-wired project — see
home battery storage and
can I add a battery to plug-in solar.
What you have to do after you plug it in
One thing, and it takes about ten minutes: tell your distribution network operator
— the company that owns the wires in your street, not your energy supplier. Under the “connect and
notify” route, GOV.UK guidance says the notification form goes to the DNO within 28 days of
installation. It is a notification, not an application; nobody can refuse it. The specification also
requires kits to carry a statement that notification of both connection and disconnection is
mandatory, so you notify again if you take the kit down. Start at
telling your DNO about plug-in solar or
how to find your DNO.
Who it actually suits
On the numbers above, plug-in solar makes sense for a household that is in during the day, has a
south-, east- or west-facing outdoor space it controls, and wants a reversible measure it can take with
it. It makes much less sense for a household that is out from eight to six with no timed loads to
shift, because most of what the panels make will leave the house for nothing. It is also, for now, the
only realistic route to self-generation for many renters and flat-dwellers — subject to permission,
which the regulations did not touch. See
plug-in solar for renters.
Frequently asked questions
Do I need an electrician?
Not to install a compliant kit into an existing, sound socket. You do need one for anything touching
fixed wiring or the consumer unit, and the specification tells manufacturers to say so. See
do you need an electrician.
Can I use an extension lead?
No. The specification requires manufacturers to state clearly that extension cables, multi-way
adaptors, RCD adaptors and travel adaptors are not permitted.
How many kits can I have?
One per household today. The government has decided the specification should allow one device per
final circuit protected by its own circuit breaker, but that only takes effect once G98 is amended to
match; until then the one-per-household limit in G98 applies.
Does it work in winter?
It works, but output collapses. December output at UK latitudes is a small fraction of June’s, and
a vertical panel narrows that gap slightly rather than closing it.
What does a kit cost?
We do not publish prices we have not collected ourselves. For reference, the DESNZ impact assessment
records European 800 W systems as “available for around £400 to £600”, excluding installation or other
ancillary costs; British retail pricing at launch is a separate question and we will publish a dated
own-survey rather than repeat retailer figures. See
how much does a plug-in solar kit cost.
Primary sources.
SI
2026/848 (legislation.gov.uk) ·
DESNZ, Plug-in solar: government response, final-stage impact assessment and Interim
Product Specification version 2, July 2026 ·
GOV.UK, Register energy devices in homes or small
businesses ·
Ofgem, Smart Export Guarantee.
General information, not legal or electrical advice — see
our editorial methodology.