The plug-in solar market in the UK is still young, and not every product on sale has been designed with UK regulations in mind. A few straightforward checks before you buy will save you problems later, both with compliance and with the amount of electricity the system actually generates.
Check the microinverter certification first
The microinverter is the most safety-critical component in the kit. It handles grid synchronisation and the anti-islanding protection that shuts the system down if mains power fails. A substandard microinverter is not just an efficiency problem; it is a safety issue.
Look for CE marking and UKCA marking on the inverter. These confirm the product has been tested against European and UK safety standards respectively. Well-known microinverter brands in this market include Hoymiles, Growatt and EcoFlow’s own STREAM unit. Avoid unknown brands with no certifications, however attractive the price.
The 800W output limit
Under UK regulations, the system must not exceed 800W of output. Most reputable kits are designed to this limit. Check the product specification rather than assuming: some kits marketed in Europe have slightly different configurations and the UK version should be clearly labelled.
G98 compliance
The product documentation should confirm G98 compliance. This is the grid connection standard that applies to small generators in the UK. If a seller cannot confirm G98 compliance, look elsewhere.
Panel quality
For the panels themselves, monocrystalline panels are the most efficient option currently available at consumer price points. IBC (Interdigitated Back Contact) and HJT (Heterojunction Technology) panels offer higher efficiency still and perform better in low-light conditions, which matters in the UK. They cost more but generate more electricity per square metre of panel area.
Check the panel efficiency rating in the product spec. Anything above 20 percent is good. The best panels on the market reach 22 to 24 percent efficiency.
Warranty
A reputable solar panel should come with a 25-year performance warranty guaranteeing at least 80 percent of rated output at the end of that period. Microinverters typically carry a 10 to 15 year warranty. Be cautious of kits with significantly shorter warranties, as they suggest lower confidence in product longevity.
Wait for BSI certification if you can
The BSI product standard expected around July 2026 will make it much easier to identify compliant products at a glance. Kits certified to this standard will be verified for UK plug-in use and will be the simplest legal route to self-installation. If your timeline is flexible, waiting a few months for certified products to reach shelves is the safest approach.