Plug-in solar has real price tags now. It also has official savings figures, worked out by the government before it changed the law. Those figures are for 800 W of panels, though, and many kits have less. So match the price to the panel size before you do the sums.
How much does a plug-in solar kit cost?
We checked shop pages on 12 October 2026. Single-panel kits ran from £336 to £650 (£670.80 at City Plumbing). Octopus sold a 460 W kit at £450 but was sold out that day. Two-panel kits ran from £456 (City Plumbing, 950 W) to £989 (UKSOL Max, 1260 W). Prices are moving fast, so treat these as a snapshot, not a promise. Our guide to where to buy plug-in solar has the shops.
How much power does a kit make?
It depends on where the panel sits, and how many panels there are. The government modelled two set-ups for 800 W of panels. Facing south and tilted at 30 degrees, it can make up to 690 kWh a year. Fixed flat to a wall that faces east or west, it makes about 378 kWh. That's close to half. Same kit, same price, very different result. A single 460 W panel makes roughly half of those figures.
How much of that power do you actually use?
Not all of it. The sun does its best work at midday, when your home may only be running the fridge. The government's sums say a home uses about 62% to 72% of what the kit makes. The rest slips out to the grid. For most kits you don't get paid for that. Which? says plug-in kits can't sell spare power the way rooftop solar can. The one exception is Octopus, which pays export only on kits bought from Octopus. Our export rates guide has the detail.
What does that save you a year?
For 800 W of panels, the government says about £110 a year facing south and tilted, and about £70 a year flat on an east or west wall. Those figures assume someone is home in the day. Most kits under £600 have just one panel of 340 to 515 W. We scaled the government's figures down to match. That is our estimate, not an official number. A 475 W panel saves about £40 to £65 a year. A 340 W panel saves about £30 to £45. Two-panel kits of 880 to 1050 W keep the full £70 to £110, because the inverter caps output at 800 W. Electricity costs 26.32p per kWh under the Ofgem price cap from October to December 2026. Every kWh of your own power you use saves you that much.
Do you pay VAT on a plug-in solar kit?
Yes. The 0% VAT deal on solar only covers a firm that supplies the kit and fits it for you. HMRC's guidance says that if energy-saving materials are supplied without installing them, the sale is standard-rated. A plug-in kit is something you buy and fit yourself. So you pay the normal 20%. The good news is that shop prices already include it.
So how long until it pays for itself?
Take the price and divide it by the yearly saving. Use the saving for that kit's panel size. City Plumbing's 475 W kit at £336 pays back in about 5 to 8.5 years. Octopus's 460 W kit at £450 takes about 7 to 11 years. City Plumbing's 950 W kit at £456 takes about 4 to 6.5 years. Screwfix's PowerXpress 920 W kit at £669 takes about 6 to 9.5 years. Per watt of panel, the two-panel kits are the better buy. The first number in each pair is a sunny, tilted spot. The second is a flat east or west wall. We run more examples in is plug-in solar worth it? Prices checked 12 October 2026.
The quick version
- Kits cost about £336 to £989, VAT included (checked 12 October 2026).
- Two-panel kits (about 920 W) save about £70 to £110 a year. One 460 W panel saves about £40 to £65, our estimate.
- A 460 W kit at £450 pays back in about 7 to 11 years. A 950 W kit at £456 takes about 4 to 6.5.