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By Rowan Halstead · Updated 23 September 2026

Screwfix Plug-In Solar: PowerXpress 800W Kit Reviewed (2026)

This article contains affiliate links. If you buy through them, we may earn a small commission at no extra cost to you. This does not influence our recommendations — we call out weaknesses as plainly as strengths.

Screwfix stocks exactly one plug-in solar kit: the PowerXpress 800W Bifacial Plug-In Solar Power Kit, product code 396MG, at £669 including VAT.

The important thing about it — and the reason it is worth a page of its own — is that it is real. It holds a genuine compliant listing under the Plug-in Solar device type on the ENA G98 Type Test Register, which is the only route that makes socket self-installation legal. Most of the brands people search for do not.

The second important thing is that the guarantee is one year, which is the shortest of any certified kit we have looked at.

Prices and register status checked 21 September 2026.

Quick Facts - Price: £669 inc VAT at Screwfix (product code 396MG) - Output: 800W — 2 × 460W bifacial panels, 920W peak panel capacity - Panels: OSDA Solar bifacial TOPCon N-type, 23.1% module efficiency - Inverter: Marstek MST-MI0800W, 800VA, dual independent MPPT - Register status: Compliant, Plug-in Solar, published 3 September 2026 - Guarantee: 1 year via Screwfix - Panel size: 1762mm × 1134mm each — measure your balcony before ordering - Battery: none included; AC-coupled battery can be added later

The Short Answer

If you want a certified plug-in solar kit from a high-street name, this is currently the only one Screwfix sells (on 26 September it was available for delivery but showed out of stock for branch collection), and it is a competent piece of hardware. The OSDA bifacial panels at 23.1% efficiency are genuinely good — better than most supermarket-tier kits — and the Marstek microinverter's dual MPPT means one shaded panel does not drag down the other, which matters a lot on a balcony.

What you are paying for is convenience and a familiar returns counter. At £669 it is roughly £200–£300 more than equivalent certified kits from trade suppliers, and the one-year guarantee is well below the market. If neither of those bothers you, it is a straightforward buy.

Is It Actually Certified? Yes — and That Is Not a Given

This matters more than any spec, so it goes first.

Since SI 2026/848 came into force on 27 August 2026, a plug-in solar kit can only be legally self-installed into a standard socket if the device holds a compliant listing under the Plug-in Solar device type on the ENA Type Test Register. The PowerXpress kit does, published 3 September 2026 under reference POWEZA/21077/V1/A1.

The distinction that trips people up: several major brands hold compliant register entries under other device types — PV or Energy Storage Device — which cover conventional systems that an electrician installs and notifies. Those listings do not transfer, which is why an Anker SOLIX kit is not something you can legally plug into a socket despite being heavily marketed in the UK — Anker holds no Plug-in Solar entry at all. EcoFlow is now the counter-example: its two kit-level plug-in submissions were recorded compliant on 22 September 2026, but only as solar-only configurations. A STREAM bundled with a battery stays an Energy Storage Device and stays outside the socket route.

Zendure is the exception, as of today. Six Zendure SolarFlow 800 configurations were listed compliant on 21 September 2026 — the first of the well-known battery brands to obtain a socket self-install route. If you want a branded kit with an app ecosystem rather than trade hardware, that is now a real alternative, though UK retail pricing for the compliant configurations is still settling.

So the Screwfix kit clears the bar that most of its better-known competitors do not.

What You Actually Get

Bifacial is a real advantage here, conditionally. Bifacial panels generate from reflected light hitting the rear face. On a balcony with a light-coloured wall or floor behind them, that is a genuine few percent. Flat against a dark railing with no gap, it is worth nothing. Mount them with an air gap and the bifacial premium starts paying.

920W of panel into an 800VA inverter is deliberate. The inverter clips output at 800VA to stay inside the regulatory cap, but the oversized panel array means you hit that ceiling for more hours of the day, and in weaker light. This is standard practice and is not a fault.

The Weak Points

The one-year guarantee. This is the real cost of buying here. Screwfix lists a 1-year guarantee on the kit. For comparison, Hoymiles microinverters carry 12 years, Anker 10, EcoFlow 5. Solar hardware normally outlives its warranty comfortably, but a microinverter is an outdoor power electronics device, and one year is a thin backstop on a £669 purchase.

The price. £669 buys a lot less here than elsewhere on the certified market:

Buying the same kit direct from PowerXpress costs £599 but adds £90 delivery, making Screwfix marginally cheaper overall — a rare case where the retail markup works in your favour.

Panel size. At 1762mm × 1134mm, these are full-size panels, not compact balcony units. Two of them need a little over 4 square metres of mounting area. Measure first; this is the single most common reason a balcony solar kit gets returned.

"Registration required." Screwfix's own listing flags this, and it is easy to skim past. See below — it is genuinely quick, but it is not optional.

Registering It: About Two Minutes

Because this is a solar-only kit within the 800W limit, it uses the notification route rather than a DNO application. You register at myplugin.solar after installation. You do not need permission in advance, and you do not need an electrician.

This is a change that a lot of older advice online has not caught up with — pages still describing a G98 application form to your DNO are describing the pre-August 2026 process for a different class of system.

• DNO Notification and G98 Explained — what changed on 27 August 2026 and what you actually have to file.
• Which Plug-In Solar Kits Are Certified? — the live register tracker, updated as entries change.
• Best Budget Balcony Solar Kits Under £500 — if £669 is more than you wanted to spend, the certified options below it.
• How Much Can You Actually Save? — realistic generation figures for a UK balcony, so you can work out payback on £669.

Should You Buy It?

Buy it if: you want a certified kit from a retailer with a physical returns counter, you have the balcony space for full-size panels, and the convenience is worth roughly £200 over trade-supplier pricing.

Look elsewhere if: you are price-sensitive (City Plumbing's DMEGC kit is £444 for comparable output), or a one-year guarantee on power electronics bothers you — and it reasonably might.

Realistic payback: at £669 and roughly 650–750 kWh/year for a well-sited south-facing installation, at the 26.32p/kWh Ofgem cap rate:

Self-consumption is the variable that matters, because exported units from a plug-in kit typically earn nothing — most Smart Export Guarantee tariffs require MCS certification, which these kits do not have. A household that is in during the day, or that shifts washing and dishwashing into daylight hours, lands nearer the top of that table. One that is out from 8 to 6 lands nearer the bottom.

• Work out your own figure — our payback calculator takes your postcode, kit cost and usage pattern rather than assuming a national average.

FAQs

Q: Does Screwfix sell plug-in solar panels? A: Yes — one kit, the PowerXpress 800W Bifacial Plug-In Solar Power Kit, product code 396MG, at £669 inc VAT as at 21 September 2026.

Q: Is the Screwfix plug-in solar kit legal to install myself? A: Yes. It holds a compliant listing under the Plug-in Solar device type on the ENA Type Test Register, published 3 September 2026, which is what permits socket self-installation under SI 2026/848. Register at myplugin.solar afterwards.

Q: What is the warranty on the Screwfix solar kit? A: Screwfix lists a 1-year guarantee. This is shorter than most certified competitors and is the kit's main weakness.

Q: Is it cheaper to buy PowerXpress direct? A: Not in practice. Direct is £599 but adds £90 delivery, totalling £689 against Screwfix's £669.

Q: Can I add a battery to it? A: Yes, an AC-coupled battery can be added separately, but note that a kit including battery storage is excluded from the socket self-install route. Adding storage changes the installation and notification requirements.

Q: How big are the panels? A: 1762mm × 1134mm each — two need a little over 4 square metres. Measure your balcony before ordering.

Q: Does B&Q sell plug-in solar too? A: B&Q has been reported as stocking kits, but we have not been able to verify a specific product or price on diy.com, so we are not publishing figures for it. Screwfix is the one we can confirm.