How much does plug-in solar cost?

A complete plug-in solar kit is a few hundred pounds, not a few thousand. That is the whole proposition — but the sticker price is not the only number, so here is the full picture.

The price range

Across the European market, where these devices have been sold for years, complete kits typically run between about £400 and £900 depending on panel count, panel quality, microinverter brand and mounting hardware. As the Great Britain market opens from 27 August 2026 we expect the same shape: entry kits around the £450–£550 mark, mainstream kits between £550 and £750, and premium two-panel kits with quality frames above that.

Solar in a Box expects to launch from around £599. Final pricing will be confirmed nearer launch, and nothing on this site is an offer for sale.

What is inside the price

• Panels. Typically one or two, up to a combined 2,000Wp DC. The largest single line item.
• Microinverter. Converts DC to mains AC and provides the mandatory anti-islanding protection. Limited to 800VA output. Brand and warranty matter far more here than on the panels.
• Mounting. Ground frame, flat-roof tilt frame, balcony brackets or wall brackets. Cheap kits skimp here first.
• Cabling and plug. The AC lead terminating in a plug for an ordinary socket.
• Documentation. Compliance paperwork and instructions, including what you need in order to register the device.

Costs people forget

• Ballast. A ground or flat-roof frame needs weighting against wind. Slabs, blocks or ballast trays: £20–£80, and worth doing properly.
• An outdoor socket. If there is no weatherproof socket where the device needs to plug in, an electrician fitting one is typically £120–£250. This is the most common genuine extra.
• Balcony brackets. Sometimes bundled, sometimes £40–£120 extra, and railing-specific.
• Consent. Free in money terms, but leaseholders and tenants may need freeholder or landlord permission — see permissions.
• Registration. No charge, but it is a required step — see registration.

On very cheap kits

There will be imported kits well under £400. Some will be fine. The things to check are whether the microinverter meets the Great Britain grid protection requirements, whether the mounting is rated for British wind loading, and whether there is anyone to talk to if the inverter dies in year three. The panels are rarely the problem; the inverter and the brackets are.

Cost against saving

Government modelling puts annual savings at roughly £110 for a south-facing device at 30° and roughly £70 for a vertical east–west arrangement — see the DESNZ impact assessment and our savings guide. Against a £599–£699 kit, that is a simple payback of roughly six to ten years.

Two consequences worth being blunt about. First, paying more for a bigger kit does not automatically improve the return, because the 800VA ceiling caps what any compliant device can deliver at once. Second, the cheapest kit is not automatically the best return either, because a failed inverter in year four wipes out the difference. Buy on inverter quality and mounting, not on watt-peak alone.

Compared with a full installation

A full MCS-certified rooftop system is typically several thousand pounds, generates several thousand kilowatt-hours a year, and qualifies for export payments. Plug-in solar costs a tenth as much and generates far less. It is not a cheaper version of the same thing — it is a different product for people who cannot or do not want to install a roof array. The comparison is laid out on our plug-in versus rooftop page.