The short version
What Modular Solar sells
Modular Solar Technologies is a UK company that sells two plug-in units. Each is one large solar panel with the microinverter built in, so there's nothing to assemble. On 11 November 2026 its site listed a 340W unit at £465 and a 475W unit at £650, both including VAT, and it says delivery, an energy meter and cables are included.
| 340W unit | 475W unit | |
|---|---|---|
| Price, Modular Solar, inc VAT | £465 | £650 |
| Price per watt of solar panel | £1.37 | £1.37 |
| Size | 1,800 × 1,200 mm, 160 mm deep on the datasheet | 1,760 × 1,250 × 160 mm |
| Weight | 35 kg | 45 kg |
| Inverter, per the product page | 400W | 400W (400VA on the datasheet) |
| Output, Midlands, unshaded, south facing | 350 kWh a year | 500 kWh a year |
| Warranty | 10 years | 10 years |
| Weatherproofing | IP67 plugs and sockets | IP67 plugs and sockets |
Modular Solar's datasheets say both units tilt to suit the season and come with a 5 m cable. Modular Solar says the 340W frame is made from recycled plastic and the 475W frame from British timber. The figures are the maker's. The web page gives the 340W unit a 200 mm depth and the datasheet gives 160 mm, so measure the one you receive.
Is the Modular Solar unit on the ENA register?
Yes. Only kits with a Compliant record on the ENA Type Test Register count as legal plug-in solar, and Modular Solar Technologies has four. We confirmed all four on 11 November 2026. Each is type Plug-in Solar and Compliant. The manufacturer name on the register is modular solar technologies limited. The 340W records are 0.34 kW. The earlier 475W record is 0.475 kW, and the later one, with the 400W inverter, is 0.4 kW. Our tracker, last checked 13 November 2026, lists the same four references.
| Register reference | Model and capacity | Inverter named | Status, published |
|---|---|---|---|
| MODUL/21168/V1/A1 | 340W Solar Unit, 0.34 kW | Hoymiles HMS-450-1T (HOYMZ/03485/V1) | Compliant, 31 August 2026 |
| MODUL/21169/V1/A1 | 475W Solar Unit, 0.475 kW | Hoymiles HMS-450-1T (HOYMZ/03485/V1) | Compliant, 31 August 2026 |
| MODUL/21440/V1/A1 | 340W Modular Solar Unit 400W inverter, 0.34 kW | Hoymiles HMS-400-1T (HOYMZ/03477/V1/A1) | Compliant, 17 September 2026 |
| MODUL/21443/V1/A3 | 475W Modular Solar Unit 400W inverter, 0.4 kW | Hoymiles HMS-400-1T (HOYMZ/03477/V1/A1) | Compliant, 17 September 2026 |
Which record is the unit you receive?
The Amazon 340W listing does not say which record it is. It gives no ENA reference and no inverter model. The 475W datasheet names the 400W inverter, which matches the later 475W record. The 340W page also says 400W, but the 340W datasheet, version 2.0, names the older HMS-450-1T inverter. All four records are Compliant, so either way the unit sits under a verified record, but ask the seller which one it has shipped.
Our guide to checking a plug-in solar kit is legal explains how to match a box to the register.
What you get for the money
Both units cost about £1.37 a watt of solar panel. That's well above an ordinary kit: City Plumbing listed a single-panel DMEGC 475W kit at £336 on 11 November. The price buys a finished unit with an energy meter and delivery, so compare what each listing includes. If the aim is the lowest cost per watt, look at our verified kit comparison.
The extras are the point. There is no frame to bolt together, the inverter is inside the panel, and the plugs are weatherproof. That suits a garden, a shed, a workshop or a flat roof where you want a unit you can place and plug in. It suits a railing less well, because 35 kg and 45 kg are a lot to hang from one.
Modular unit or a standard plug-in solar kit?
A standard plug-in solar kit usually has two or more panels, a microinverter and a mounting kit, and you put it together yourself. That DIY step is where a modular unit differs. Each solar panel arrives with its inverter fitted, so there's no mounting kit to match and no inverter to pair. Check what each kit includes before you compare prices.
Both routes feed solar power into a household socket under the same UK regulations. Neither is a full solar installation, so a qualified electrician isn't needed to plug one in, as long as the device is on the register and you follow the one-device rules. The inverter, not the solar panel, sets the maximum power a unit can export, which is why the 475W solar panel pairs with a 400VA inverter.
The trade-off is choice. A kit lets you pick the supplier, panel and mount. A modular unit is a small solar system in one piece, and you scale it by adding a second unit within the device limits.
How much will it save?
Modular Solar says the 340W saves up to £100 a year and the 475W up to £130 a year, from 350 kWh and 500 kWh a year in the Midlands. It also quotes a payback of 4.5 years and says the units are 35% cheaper than rooftop solar. We haven't checked those two claims.
Our own sum is simpler. At 26.32p per kWh, the Ofgem cap rate for October to December 2026, 350 kWh is worth about £92 and 500 kWh about £132, but only if you use every unit in the home. Shade, direction and export all pull the figure down. Our savings calculator lets you test your own roof or garden.
Where to buy it
Modular Solar's website sends buyers to Amazon UK, and each unit has its own listing. On 11 November 2026 the 340W Amazon listing showed Modular Solar as the seller and dispatch within 4 to 5 days. That listing does not name an ENA reference or an inverter model. We don't print Amazon prices, so open the listing to see today's number and delivery date.
Our where to buy guide covers the other retailers that sell verified kits.
Before you plug it in
- Register it. Tell your network operator through myplugin.solar. Our registration guide has the four steps.
- Skip the battery. Neither unit includes battery storage, and adding one means leaving the plug-in route.
- Count your devices. Modular Solar says you can link two units, but the UK limits on devices per home and per circuit are tighter. Read our one-device explainer first.
- Check the weight. Mounting hardware, a wall or a flat roof must carry 35 kg or 45 kg, plus wind. Get permission from a landlord or freeholder if you need it.
- Keep the paperwork. Save the order page and the datasheet. They show which record the unit belongs to if anyone asks.
Verdict
Buy a Modular Solar unit for simplicity and a verified register entry, not for the lowest price per watt. The 475W is the better buy if you can carry and mount 45 kg. The 340W suits a smaller space. We haven't tested either unit, so this page compares what the maker, the register and the retailer say.
Frequently asked questions
What is a modular plug-in solar unit, and how does it work?
It's one solar panel with a microinverter built in. The panel makes direct current, the inverter turns it into household alternating current, and a cable with weatherproof plugs connects to a socket. Modular Solar says an energy meter comes with each unit, and that the 340W and 475W versions are rated IP67 at the plugs and sockets.
Are plug-in solar units legal and safe to use in the UK?
Yes, as far as the register shows. Modular Solar has four records on the ENA Type Test Register under the Plug-in Solar type: a 340W and a 475W unit, each in two inverter versions. All four were confirmed Compliant on 11 November 2026, and our tracker, last checked 13 November 2026, agrees. The manufacturer name on the register is modular solar technologies limited. The Amazon 340W listing names no ENA reference and no inverter model, so ask the seller which record your unit falls under.
How much does the Modular Solar plug-in unit cost?
Modular Solar's own site priced the 340W unit at £465 and the 475W unit at £650, both including VAT, on 11 November 2026. It says delivery, an energy meter and cables are included. Amazon UK sells both, and we don't print Amazon prices because they change through the day.
Where can I buy the Modular Solar unit?
Modular Solar's website sends buyers to Amazon UK, where each unit has its own listing. On 11 November the 340W Amazon listing showed Modular Solar as the seller, with dispatch within 4 to 5 days. That listing gives no ENA reference and no inverter model. Check the date on your own listing before you order.
Should I buy the 340W or the 475W unit?
Buy the 475W if you've got the space and a wall or frame that can carry 45 kg. It costs about the same per watt as the 340W, so the choice is size and weight. The 340W is 10 kg lighter at 35 kg.
Can I connect two Modular Solar units?
Modular Solar says you can link two units with the cables supplied. The UK plug-in rules are stricter than that on how many devices one home or circuit can run, and they have changed more than once. Read our one-device explainer before you buy a second unit.
How much will a Modular Solar unit save?
Modular Solar quotes up to £100 a year for the 340W and up to £130 for the 475W, from an annual output of 350 kWh and 500 kWh in the Midlands, unshaded and south facing. At 26.32p per kWh, the Ofgem cap rate for October to December 2026, those outputs are worth about £92 and £132 if you use every unit yourself. Anything you export earns less. The government's own estimate for plug-in solar is £70 to £110 a year.
Do I need to register a Modular Solar unit?
Yes. Tell your network operator through ENA's myplugin.solar service, as you would for any plug-in solar device. Our registration guide walks through the four steps.
Related reading
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City Plumbing Plug-In Solar Kits Review (2026): Worth Buying?
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