New UK plug-in solar rules: savings smaller than they seem, says TechRadar analysis

But being legal does not mean simple. TechRadar points out that the market sells three very different products under the general banner of "plug-in solar": solar-only kits, battery-only power stations, and solar-plus-battery systems. Of these, only the first is covered by the new rules. Battery-only power stations store grid electricity for later use and still need professional installation. Solar-plus-battery systems do both, and they are also not covered by the new regulations.

For the question consumers care about most—how much can you save—TechRadar crunched the numbers for all three scenarios. For solar-only kits, EcoFlow's standard kit of two 400W panels and a microinverter is claimed to save up to £115 a year, a figure close to the government's estimate of "up to £110 a year." The hardware costs about £399, giving a payback period of about four years. However, independent estimates are more cautious: without a battery, households can only self-consume 25-40% of the generated power. The rest is wasted because there is no battery to store it and, without MCS certification, no export tariff through the Smart Export Guarantee. Realistic savings are therefore put at £40-£85 a year. TechRadar believes a sensible expectation is £70-£110, weighted toward the lower end unless daytime electricity use is unusually high.

Battery systems are a different game. By charging when electricity is cheap and discharging during peak hours from 4pm to 7pm, they can yield larger savings. But plug-in batteries are not yet legal in the UK, so users still need professional installation, which adds upfront costs.

TechRadar concludes that while the new rules make plug-in solar legal, "legal" and "cost-effective" are two different things. Consumers should carefully distinguish between product types and treat advertised savings with caution.