Plug-in solar panel kits are set to go on sale in the UK this Thursday, just in time for Britons to catch the end of the sunny weather.

British company UKSOL, selling its one-panel solar kit for £699, has become the very first to meet regulatory compliance for the devices.

It will be on sale for delivery through Argos and other suppliers on 27 August. But plug-in solar products are not expected to be widely available to buy inside supermarkets or other high-street stores before the end of summer.

There had been expectations that plug-in solar kits would be available for around £400 as part of the Government’s push to get widespread take-off this summer.

But experts said the cost of some plug-in products may be higher than expected – explaining that prices will vary depending on the size and level of power different kits can generate.

There are still hopes that prices will come down in future, if the self-install panels become as popular as they are in Germany and other parts of Europe.

Regulation changes on Thursday

UK households will be permitted to use compliant devices from 27 August after Labour ministers pushed through legal changes last month.

UKSOL was the first company to get their plug-in solar kits listed as compliant by the Energy Networks Association (ENA). Two of its kits – designed for mounting in the garden, rather than on balconies – will be on sale from that date.

Argos and City Plumbers, a builders’ merchants with 350 branches, confirmed the plug-in solar kits will be available for households to buy.

The kits will also be available on UKSOL’s website and from other specialist suppliers. But they will initially be available only for delivery, rather than by picking up in store.

Retailers such as Lidl, Asda, B&Q, Currys, Screwfix and Wickes have all expressed interest in solar kits.

None of the firms has set a specific launch date for the devices but the Government expects some major retailers to have the kits on sale for delivery on 27 August.

However, the expectation is that they will not be available to buy in the supermarkets aisles or inside retail branches for a while, The i Paper understands.

Major outlets are still working out the logistics of stocking large products, so it could take several weeks before any are available in store.

First plug-in kits will reduce energy bills

UKSOL’s 460W single panel system – which comes with a 800W microinverter that allows the panel to start generating power – will sell for around £699. It also comes with a mounting kit and an app to monitor its performance.

The more powerful 890W system will sell for £999. This two-panel system helps to generate more power when sunshine is low in autumn and winter – even though the microinverter will cap the level of electricity at a maximum of 800W.

The prices include VAT but do not include home delivery, which may cost more.

“It’s exciting,” said chief executive Andrew Moore. “It’s going to give people a feel-good factor because they’re going to generate some of their own power in an eco-friendly way.

“It’s going to reduce their energy bills, and means less reliance on energy companies,” he added.

The amount of power users can generate has been limited to 800W per electricity circuit by the Government.

The Department for Energy Security and Net Zero (DESNZ) has estimated that plug-in solar users will be able to reduce energy bills by £70 to £110 a year.

“We think that with the bigger kit, if you can generate something close to 800W, the saving could more than that,” said Moore.

“But how much is difficult to say. It depends on where they are placed, if they’re away from shading, how much sun there is.”

Supermarkets need time ‘to deal with logistics’

UKSOL is hoping that more major outlets will start selling the devices soon. Moore said retailers are “very keen”, before adding: “The availability may be limited at first, so that could be frustrating for people. It may take a while.”

Specialist supplier Hampshire Generators said they expect to soon start selling a smaller plug-in solar panel kit – with a less powerful 400W microinverter – for between £350 and £450.

Managing director Andrew Williams said he expected the kit, which can be clipped onto balconies, to become ENA compliant in the coming days.

But it may take a while before supermarkets and big retailers start selling a range of plug-in kits in store. “They need to get stock together and deal with those logistics,” said Williams.

It could mean many people waiting until after winter to invest in plug-in solar, the supplier warned. “It’s a shame, because the weather is starting to change. It may have to be something that takes off in spring.”

Hemal Morjaria, chief commercial officer at City Plumbing, said the retailer would have UKSOL plug-in solar systems “available for purchase either online or in branch” on Thursday.

“Due to the size and nature of the products, these kits will not be held in store but available for home delivery,” Morjaria added.

Hopes for prices to come down

Expectations that all kinds of solar plug-in kits would be available for around £400 had been unrealistic, said experts.

“The price will vary quite a bit, depending on how much power they can generate, and whether it comes as part of a kit that is ready to mount,” said Dylan Ryan, an energy engineering expert at Edinburgh Napier University.

Solar Energy UK said it expects plug-in solar costs to come down if the devices take off in the UK like they have in Germany.

“As demand is fulfilled and supplies increase, prices would be expected to fall over time,” said Gareth Simkins, spokesperson for the trade association.

A spokesperson for ENA, which represents the UK’s energy network operators, said only a “limited number” of solar plug-in devices had become compliant so far. But compliance was “moving at pace”, they added.

A DESNZ spokesperson said: “Plug-in solar panels will be available to order this Thursday from retailers including Argos.”

The “transformative” plug-in technology “can save people hundreds of pounds on their bills”, they said. Legal changes follow rigorous safety testing which shows “compliant panels are safe and compatible with UK wiring”, they added.