A fortnight ago we covered the rewrite of the domestic solar permitted development rules, which wrote plug-in solar into English planning law for the first time. The other half of that story landed on 26 August 2026, when DESNZ announced that plug-in solar panels are legal to buy and use across Great Britain from 27 August — the same day the planning changes came into force.
This is the sort of change that reaches assessors sideways. You won’t see it in an Approved Document, but you will get asked about it: by homeowners on an RdSAP visit, by developers wondering whether it helps a Part L result, and by landlords eyeing an EPC band.
What the kits actually are
A plug-in solar kit is exactly what it sounds like: one or two panels that stand on a balcony, terrace, wall or patch of garden and connect to the home through an ordinary 13-amp plug and socket. No installer, no consumer-unit work, no scaffolding.
The government’s numbers:
- Each kit produces up to 800W of power.
- That is enough for up to 20% of an average home’s electricity use — DESNZ’s illustration is a fridge, TV, router, laptop, phone charger and games console running together while the sun is out.
- Estimated saving: up to £110 a year.
The legal change follows independent safety testing across the key electrical elements, and DESNZ says the resulting UK safety specification is more stringent than Germany’s — the market where the technology is already mainstream, with around half a million devices plugged in last year.
Major retailers have worked with government on the rollout. Currys, B&Q, Screwfix and Amazon are named as delivery partners, with Amazon, Argos, Currys and Wickes committing to stock the panels in stores and online.
The permission checks that still apply
“Legal to buy” is not “install it anywhere”. Before buying or fitting a kit, the government asks people to check whether their property needs:
- permission from a landlord, building owner or freeholder;
- planning permission; or
- listed building consent.
Whether those permissions are granted is a matter for the landlord, freeholder or council — government has simply encouraged them to consider each case on its merits.
Layered on top of that, in England, is the permitted development framework in SI 2026/896, which amended Part 14 of Schedule 2 to the GPDO with effect from 27 August 2026. Two limits catch plug-in solar in particular:
- Plug-in solar is not permitted development where any part of it would be installed on a wooden wall, balcony, fence, gate or other enclosure, or on any timber-clad part of a house or block of flats.
- The usual heritage carve-outs bite: nothing on a listed dwelling or block of flats, nothing on a scheduled monument, and in a conservation area or World Heritage Site nothing on a wall, balcony or roof enclosure fronting a highway.
The combustible-substrate exclusion is the one worth remembering, because timber fences and balcony balustrades are precisely where a lot of people will instinctively want to hang a panel.
One jurisdictional wrinkle: the legality of the products applies across Great Britain, but the GPDO amendment is England only. Scotland and Wales have their own permitted development regimes.
Does it count in SAP, RdSAP or an EPC?
Short answer: nothing in this announcement changes the assessment methodology. There is no new convention, no new SAP input, and no change to Approved Document L.
That matters, because the obvious client question — “will this improve my EPC?” — doesn’t have a comfortable answer yet. Plug-in solar is user-installed, moveable, and typically has no commissioning paperwork, no MCS certificate and no fixed orientation or pitch. Those are exactly the things an assessment relies on to credit a PV array: declared capacity, orientation, pitch and overshading, evidenced at the time of the visit. A kit that can be unplugged and taken to a new flat on moving day is a poor fit for a certificate that lasts ten years.
For new build, the point is sharper still. The Future Homes Standard notional dwelling assumes a meaningful area of roof-mounted PV, and Part L compliance is demonstrated against a designed, fixed, documented array. An 800W plug-in kit is not a substitute for specifying the real thing — and it isn’t something Building Control will accept as part of a compliance package.
Our reading: treat plug-in solar as a bill-saving consumer product, not an energy-assessment input, unless and until a convention says otherwise. If you’re asked, that’s a defensible line to take, and it’s worth putting in writing to the client.
The market context
The announcement lands in an already busy year for solar. MCS figures cited by DESNZ show almost 150,000 certified solar installations in the first six months of 2026 — up 17% on the previous record start to a year in 2025, or roughly one installation every 74 seconds. Certified battery installations reached 36,000, close to double the same period last year.
The Energy Networks Association’s response also flagged something to watch: network operators expect the registration process for microgeneration to evolve as these devices spread. That’s the kind of quiet administrative change that eventually shows up in what assessors and installers are asked to evidence.
What to do with this
If you advise homeowners, the useful checklist is short: check the tenure and heritage permissions first, keep the panels off timber, and don’t promise an EPC improvement.
If you’re working on new build, the change doesn’t move your compliance model at all — which is rather the point. Solar only ever earns its keep in a Part L calculation when the fabric underneath it is right; PV bolted on to compensate for a leaky envelope and untested junctions is an expensive way to fail a design-stage assessment. If you’d like the PSI values and fabric numbers modelled properly so your renewables aren’t papering over losses you could have designed out, get in touch and we’ll tell you how we’d approach it.
Sources: Households can save as plug-in solar panels come to market, DESNZ, 26 August 2026, GOV.UK · The Town and Country Planning (General Permitted Development) (England) (Amendment) Order 2026 (SI 2026/896), legislation.gov.uk · Plug-in solar panel checklist, Energy Saving Trust · Record number of UK households combining renewables, MCS