The UK Plug-In Solar Market in 2026: Regulations, Players, and What It Means for PV Professionals

What is changing in the UK?

Until now, connecting a solar system to a UK mains socket has not been permitted under BS 7671 wiring regulations. Any solar installation, no matter how small, has required a qualified electrician to connect the system via a fixed electrical circuit.

The government has now committed to changing this. Two regulatory updates are in progress.

BS 7671 Amendment 4 was published on 15 April 2026. This updates the UK wiring regulations to accommodate sub-800W solar systems connected to domestic mains sockets. The amendment addresses the technical concern around ring main circuits, which are unique to UK household wiring and require specific safety provisions for backfed current.

The BSI product standard for plug-in solar devices is expected around July 2026. This standard will define the certification requirements that manufactured kits must meet before they can be sold as plug-and-play products in UK retail. Until this standard is published, no kit can legally be marketed as a true plug-in product in the UK.

The government has also confirmed it will work with the Energy Networks Association, distribution network operators, and Ofgem to update the G98 distribution code. This will simplify the process for households to notify their local DNO when connecting a small solar system, similar to the streamlined notification process used in Germany.

The market opportunity

The UK has approximately 5 million households living in flats, many of which have balconies, terraces, or communal outdoor spaces but no access to rooftop solar. Add to this the millions of homeowners with gardens, sheds, and fences but no interest in or budget for a full rooftop installation, and the addressable market for compact solar is significant.

Germany provides the clearest reference point. Analysis from Bundesverband Steckersolar suggests that over 400,000 plug-in solar systems were registered in Germany in 2025 alone. In a mature market with supportive regulations and retail availability through supermarkets and hardware stores, uptake has been rapid.

The UK market is likely to follow a similar trajectory, though with some differences. UK housing stock relies heavily on ring main circuits rather than the radial circuits common in continental Europe. This has been the primary technical barrier to plug-in solar in the UK and is the reason the BS 7671 amendment was necessary. With that barrier now being removed, the pace of adoption will depend on product availability, pricing, and consumer awareness.

Current estimates suggest that certified plug-in solar kits will be available in UK shops from late summer or autumn 2026.

Who is already operating in this space?

While much of the UK market is waiting for the new standards to take effect, a number of UK-based companies have already positioned themselves in the compact solar segment.

Thunder Energy, a London-based company, has not waited for plug-in regulations. Thunder has been installing compact solar systems on balconies, garden fences, and walls using a compliant hardwired connection method: a fused spur on a dedicated radial circuit, installed by a qualified electrician. Their Storm kits use lightweight flexible panels weighing 3.5 kg each, paired with the Hoymiles HMS-800W-2T microinverter. Thunder offers both DIY kits for self-installers across the UK and a professional installation service in the London area for £399. The company has completed real multi-unit projects, including a residential block in North London where balcony and garden solar systems were installed across six flats. This kind of early market activity demonstrates that demand exists well ahead of the regulatory changes, and that compliant installation routes are already available for households that do not want to wait.

Plug In Solar Ltd, based in Sussex, has been selling DIY solar kits in the UK for several years, primarily using Enphase microinverters. Their kits range from small balcony systems to larger rooftop arrays and are designed for self-installation with professional electrical sign-off.

As the BSI product standard is published and retail availability expands, more companies are expected to enter the market. But the early movers already operating in this space have a significant advantage in brand recognition, installation experience, and customer trust.

Design and planning considerations for PV professionals

For system designers and PV planners, the UK plug-in solar market introduces some specific technical considerations.

Ring main compatibility. UK homes use ring final circuits protected by 32A MCBs. An 800W plug-in solar system adds approximately 3.5A to the circuit. While this is well within the ring main’s capacity, system designers should be aware that the BS 7671 amendment includes specific provisions for how plug-in solar interacts with ring circuits. The IET has published guidance on this topic alongside the amendment.

Vertical mounting is the default. Unlike rooftop solar, most plug-in solar in the UK will be mounted vertically on fences, walls, and balcony railings. This significantly affects yield calculations. A south-facing vertical surface in London receives approximately 775 kWh/m2/year, compared to roughly 1,050 kWh/m2/year at an optimal 35-degree tilt. PV planning tools like PV*SOL should be configured accordingly when modelling plug-in solar installations, with vertical orientation set as the baseline rather than the exception.

Lightweight panel specification. Many UK balconies, timber fences, and garden structures cannot support the weight of conventional rigid glass panels. Flexible panels in the 3 to 5 kg range are becoming the preferred option for these applications. System designers should factor panel weight into structural assessments, particularly for older housing stock common across UK cities.

G98 notification. All systems under 3.68 kW require a G98 notification to the local DNO within 28 days of installation. For plug-in solar, this process is expected to be simplified further under the updated regulations, but it remains a requirement that should be built into the installation workflow.

Fire safety on facades and balconies. Research published in February 2026 by OFR Consultants for the Building Safety Regulator found that solar panels mounted on balconies and facades can create semi-enclosed spaces that trap heat. The final BSI product standard is expected to include provisions around non-combustible surfaces and minimum gap heights for balcony installations. PV professionals should monitor this standard closely, as it may impose constraints on mounting configurations.

What this means for the wider solar industry

Plug-in solar is not a replacement for rooftop PV. An 800W system generates a fraction of what a properly designed rooftop array can deliver. But it opens solar to a demographic that rooftop installations cannot reach: renters, flat dwellers, and households without suitable roof access.

For PV planning firms and installers, this creates two opportunities. First, plug-in solar can serve as an entry point that leads to larger installations. A household that starts with a 710W balcony kit and sees real savings on their electricity bill is far more likely to invest in a full rooftop system when the opportunity arises. Second, the multi-dwelling residential segment, blocks of flats with communal outdoor space, represents a growing market for professional design services combining plug-in solar with shared rooftop systems.

The UK government’s Solar Roadmap targets 47 GW of solar capacity by 2030. Plug-in solar will contribute only a small fraction of that total, but by removing barriers to entry for millions of households, it could accelerate public engagement with solar energy in a way that benefits the entire industry.

Key dates for 2026

• 15 April 2026: BS 7671 Amendment 4 published, updating UK wiring regulations for plug-in solar.
• July 2026 (estimated): BSI product standard expected, defining certification requirements for plug-in solar kits.
• Summer/Autumn 2026: First certified plug-in solar kits expected to appear in UK retail.

For PV professionals planning to work in or supply the UK market, now is the time to understand the regulatory framework, evaluate the product landscape, and prepare for what could be one of the fastest-growing segments in European residential solar.

Heval Arcan