Although the main point of using plug-in solar panels is to reduce your energy costs in the here and now, they still involve a level of investment that needs consideration.
And, while they are far from the costs of standard solar panels, is it safe to assume that as they are cheaper to buy upfront, the payback period will be quicker?
If, like us, you're trying to work out the cost vs savings vs payback equation, you're in the right place. We asked experts to crunch the numbers and here's what they came back with.
Cost vs savings for plug-in solar panels
Let's break this down into something that's easily understandable by tackling costs and energy savings first.
As plug-in solar panels can generally be set up and installed yourself (as our reviewer discovered for herself), there are no extra costs for hiring a professional to set them up. At the very most, if you're not a regular DIYer, and are using a wall-mounted version, you may need a general handyman with the right tools for drilling into brick walls.
That aside, the costs for plug-in solar panels vary depending on the size and where you buy them from. Legally compliant plug-in solar panels are the only ones you should ever be considering, and for a single panel you can expect to pay around the £500 mark, with a two-panel system costing upwards of £800.
So, what savings will you get for your investment?
“According to external research from Carbon Brief, published in April 2026, an 800W plug-in solar panel system costing around £500 could generate approximately 400kWh of usable electricity a year in a realistic setup, rising to around 820kWh if positioned optimally," said Uswitch's solar expert, Alvaro Iturmendi.
"This equates to roughly 1-2kWh of electricity per day on average, which, based on an electricity price of 27p per kWh, could save households around £105 a year on their energy bills."
However, as the technology is still relatively new, only time will tell if the generation vs savings will amount to as much as is hoped. As the data simply isn't available yet, Jon Skinner, founder of Glow Homes suggests erring on the side of caution if accepting these sums as fact.
"Plug-in solar panels are being sold as a shortcut to cheaper energy bills, but homeowners need to understand that you can't simply plug your way to instant savings. The sunshine might be free, but the equipment certainly isn't.
"An 800-watt plug-in system might generate an average of one to two units of electricity a day across the year, depending on its positioning and location. On a bright summer day, you'll get considerably more."
But what about using plug-in solar panels in winter? Despite the fact, like solar PV, they need daylight rather than sunlight, "on a miserable December afternoon, you might barely generate enough to make a cup of tea," he warns, which leads us nicely onto the next point – cost vs payback time.
A dual panel kit for those with larger gardens or extra space to maximise on plug-in solar panel energy generation
A smaller single panel model that comes with a ground mount and is suited to those with smaller available outdoor space
Alvaro works on comparing solar and battery prices and tariffs for Uswitch and has been involved in the industry for over five years.
Jon Skinner is the founder of Glow Homes, a Surrey-based, but UK-wide residential energy company created to make home electrification clearer, better designed and easier to live with. Glow Homes takes a “home before hardware” approach, designing complete energy systems around each property, household and long-term ownership plan rather than simply selling individual products. Jon founded Glow Homes after experiencing the challenges of electrifying his own property and recognising the need for more joined-up advice.
Costs vs payback period for plug-in solar panels
Here is where the maths really needs examination say our experts, as anyone looking for a quick return on their investment may need to reassess their reasons for installing plug-in solar panels in the first place.
If you look at it in its most basic terms, if you pay around £500 for your plug-in solar panels and generate around £100 of savings a year, this "means the initial cost of the panels could be recovered in roughly five years. After this point, households could begin making net savings," says Alvaro Iturmendi.
“However, payback periods can vary," he confirms, "with other estimates suggesting it could take around four to seven years to recover the initial investment, depending on the cost of the system and how much of the electricity generated is used.”
Or, in other words, if recouping your investment is your main priority, you will have to accept that it may take a minimum of four years to do so, and as a result, all you will do in this time is pay off the cost of your panels, rather than saving on your energy bill.
And, picks up Jon Skinner, "with systems costing anywhere from £500 to £1,200, and typical annual bill savings estimated at £70 to £110, homeowners could realistically be looking at anything from five years to well over 15 years before they've recovered their investment.
"Spend £1,200 on a system that only saves you £70 a year and you're looking at more than 17 years just to break even," he adds.
The hidden catch
There's also one key point Jon Skinner is keen to point out that he thinks homeowners may forget to factor into the equation. Unlike solar PV which can store any electricity generated to a solar battery for use later on, it's not yet the case with plug-in solar panels. They aren't yet approved for use in this way, or for the Smart Export Guarantee.
"You don't save money on the electricity your panels generate," expands Jon, "you save money on the electricity they generate that you actually use. If you're out all day, your panels are shaded or they're pointing in the wrong direction, those impressive-looking savings projections can quickly unravel," he warns.
That said, Jon confirms that plug-in solar can certainly have value when installed in the right home and with the right goals in mind.
"I'm a huge advocate of solar technology, but homeowners need to look beyond the sticker price and calculate the actual return. A cheap system that takes 15 years to pay for itself isn't necessarily a bargain.
"But, plug-in solar can be a brilliant entry point for people who cannot install a full rooftop system, particularly renters and flat owners," he confirms. "My advice is simple: do the maths before you do the installation. Sunshine is free. Bad maths is expensive.”
In summary, the main issue with plug-in solar panels is that the data simply won't be available yet to give a highly accurate response.
However, as an add-on purchase to your home, that is costs less than standard solar panel costs, and as a piece of technology that you can take with you if you move home, perhaps the key is to see it less as an investment, and more of a energy bill bonus.
Are they worth it? It's a question only time will reveal the answer to, but with ongoing rising energy costs, anything that may help to reduce bills will likely still be seen by many homeowners as something worth pursuing.
