Plug-In Solar Review
Thunder Bolt Plug-In Solar Kit UK: 460W & 920W Review
Two of the very first self-install kits on the ENA register, built around a Hoymiles microinverter with a 10-year warranty. Here's what you get, who it suits, and how to get £20 off with our reader code.
Last reviewed: 30 September 2026
Quick answer: Thunder Energy's Bolt kits are genuine self-install plug-in solar, on the ENA register as Compliant since launch day (27 August 2026). The Bolt 460W is one panel for £549.99 and the Bolt 920W is two panels for £749.99, both running through a Hoymiles 800W microinverter with a 10-year warranty. Our code COOLPOWER20 takes £20 off either kit. They're big, rigid panels made for gardens, walls, sheds and flat roofs rather than balcony rails, and they cost more than the cheapest City Plumbing kits, but you get a stronger warranty, a free setup video call and a UK company to deal with.
*Rough estimate for the 920W kit on a south-facing, unshaded site with good daytime use. Use the calculator below for your own figure.
Disclosure: Thunder Energy pays Cool Power Co a commission on orders placed with code COOLPOWER20. It doesn't change our verdict and you pay less, not more. We haven't had hands-on time with the Bolt kits yet; this review is based on Thunder's published specs, the ENA register and direct contact with the company.
What You're Actually Buying
Both kits use the same parts. The panels are Thunder's own 460W N-type TOPCon rigid panels (23% efficiency, 1762 × 1134mm, 21kg each), and every kit comes with a Hoymiles HMS-800-2WB microinverter: 800VA output, two independent MPPT inputs, IP67 and fanless. You get Thunder's bracket set, DC extension cables, disconnect tools and a UK 3-pin cable that plugs into a normal outdoor socket. The inverter connects over Wi-Fi and Bluetooth so you can watch generation in Hoymiles' S-Miles Home app.
There's no battery in either kit. What the panels produce powers whatever's running in your home at the time, and any surplus goes to the grid unpaid, because plug-in systems can't currently get Smart Export Guarantee payments. That's why these kits pay back best if someone's home in the day or you run the washing machine and dishwasher while the sun's out.
Cool Power Co Reader Discount: £20 Off
Enter this code at checkout on thunderenergy.co.uk to take £20 off each Bolt 460W or Bolt 920W kit. It's twice the saving of Thunder's own public code.
Legal Status: Compliant Since Launch Day
We checked the ENA register rather than relying on Thunder's own marketing.
Self-install plug-in solar became legal in Great Britain on 27 August 2026, capped at 800W of output per household. Both Bolt kits went on the ENA Connect Direct register as Compliant Plug-in Solar devices that same day: THUNE/21203/V1 for the Bolt 460W and THUNE/21204/V1 for the Bolt 920W. Unlike several brands, neither has dropped off the register since.
You still need to tell your DNO. Plug-in solar counts as generation connected to the grid, so you notify your Distribution Network Operator using the G98 form after it's running. Thunder gives you the system details and ENA reference to fill it in.
Register status can change. Check the live ENA register on the day you buy, and that the reference on your kit matches. Our balcony solar legal guide explains the rules in full.
Bolt 460W — One Panel
1 × 460W panel, Hoymiles 800VA microinverter. The simplest, cheapest way into Thunder's range.
| Mounting | List price | With COOLPOWER20 | |
|---|---|---|---|
| Ground or wall mount | £549.99 | £529.99 | Buy with code → |
| Flat roof mount | £584.98 | £564.98* | Buy with code → |
*Flat-roof price from Thunder's store listing (~£35 extra per panel). We've asked Thunder to confirm the code covers the flat-roof option too.
With one 460W panel the inverter never gets near its 800W limit, so you're paying for headroom you don't use. It suits a small garden or shed roof, or anyone who wants to start small. Because the HMS-800-2WB has two inputs, you could in principle add a second panel later, but check with Thunder that it's the same panel and that your setup stays within the compliant configuration before you do.
Bolt 920W — Two Panels
2 × 460W panels on one Hoymiles 800VA microinverter. The better-value kit and the one most people should buy.
| Mounting | List price | With COOLPOWER20 | |
|---|---|---|---|
| Ground or wall mount | £749.99 | £729.99 | Buy with code → |
| Flat roof mount | £819.96 | £799.96* | Buy with code → |
*Flat-roof price from Thunder's store listing (~£35 extra per panel). We've asked Thunder to confirm the code covers the flat-roof option too.
The panels add up to 920W, but the inverter caps output at 800VA, the legal limit. That's deliberate: the extra panel capacity means you hit that 800W ceiling for more of the day and produce more in cloudy weather and in the mornings and evenings. For £200 more than the 460W kit you get roughly twice the generation, so the 920W kit pays back faster. You'll need space for two 1.76m panels at 21kg each.
The Good and the Not-So-Good
What we like
- On the ENA register as Compliant since launch day, and never dropped off
- 10-year microinverter and 25-year panel warranties
- Hoymiles inverter with app monitoring
- Free setup video call and 14-day returns
- £20 off with our code
What to weigh up
- Dearer than City Plumbing's DMEGC kits (from £444 for two panels)
- Big 21kg panels, not sold for balcony rails
- No battery, and no export payments on plug-in systems
- A newer company, so less of a track record than Octopus or Hoymiles itself
How the Bolt 920W Compares
The main compliant two-panel kits on sale right now. All are on the ENA register as Compliant.
| Kit | Price | Panels | Microinverter | Mounting | Warranty |
|---|---|---|---|---|---|
| Thunder Bolt 920W | £729.99 with code | 2 × 460W | Hoymiles 800VA | Garden, wall, flat roof | 10-yr inverter, 25-yr panels |
| Octopus Energy 2-panel | £650 | 2 × 460W JA Solar | Fox ESS 800W | Wall or ground | Check with Octopus |
| City Plumbing DMEGC 930W | £444 | 2 × 465W DMEGC | Hoymiles HiFlow 800W | Wall or ground | Check with City Plumbing |
| EcoFlow STREAM Facade 800 | £449 | 2 × 400W | EcoFlow STREAM 800W | Wall | Check with EcoFlow |
On price alone, City Plumbing's DMEGC kits are hard to beat, and Octopus is cheaper too. Thunder's case is the warranty, the proven Hoymiles inverter and the support that comes with it. If you want the cheapest compliant kit, go City Plumbing; if you'd rather pay a bit more for a longer warranty and someone to call, Thunder with our code narrows the gap. See every option on our plug-in solar hub.
Estimate Your Savings
A rough estimate based on your home, panel direction and region. Prices include the £20 code.
Assumes ~900 kWh a year per kW at a south-facing baseline, with the 920W kit treated as 800W because of the inverter cap. With no battery we assume you use around 50% of what's generated in the day, at the October 2026 price cap of 26.32p/kWh. Plug-in systems don't earn export payments. Real results depend on shading, weather and when you use power.
How to Buy (and Get £20 Off)
From order to generating power in five steps.
Remember to enter COOLPOWER20 at checkout. Thunder offers 14-day returns for a full refund.
Frequently Asked Questions
Related Guides
Ready to Fit Plug-In Solar Yourself?
Use code COOLPOWER20 for £20 off a Thunder Bolt kit, with free delivery and 14-day returns.
ENA Compliant · Free UK delivery · 14-day returns