Solar panels won’t slash energy bills on their own – an expert explains how to maximise savings
Energy bills in the UK are still expected to rise in the coming months, putting more pressure on household budgets despite the shaky ceasefire in the Gulf.
Meanwhile, use of solar power is growing across the UK, achieving 22 gigawatts (GW) of solar capacity from nearly 2 million installations, by February 2026.
In March, solar panel sales in the UK rose sharply, with one renewable energy firm reporting a 54% increase in sales. While rooftop solar is often seen as the most effective way to reduce electricity costs , it is not an option for all households, especially those living in flats or rented homes.
The UK government has plans to expand the use of solar as part of a wider focus on energy security. And it has now said plug-in solar will soon by available in the UK.
These are small systems, typically around 800W, that can be installed on balconies or external walls and connected directly to a household socket, without needing an electrician. They could offer a more accessible option for households that cannot install on rooftops.
Although standards and safety guidance is yet to be set in the UK, these plug-in systems are already widely used in other parts of Europe. Some sources suggest there were around 4 million units being used in Germany in 2025.
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How about plug-in solar?
The amount of electricity a plug-in solar system generates is relatively small.Performance can also vary depending on where it is installed. Factors such as the direction a balcony faces, shading from nearby buildings and how the panels are positioned can all reduce how much electricity is produced.
A typical UK household uses around 2,700-3,000 kilowatt hours (kWH) of electricity each year. Using a basic online calculator, a small 800W plug-in solar system, when vertically mounted on a balcony, is likely to generate around 150-350kWh, depending on orientation and shading. This means the system can provide about 5-12% of the electricity a home uses over a year. This could help a bit with bills, but not hugely.
What makes more of a difference is the time you use your energy. Solar generates electricity during the day, but most households need more in the evening. So much of this energy may go unused if the home is unoccupied during the day.
Benefits of batteries
To benefit the most from solar, households need to consider how they use electricity.
One simple way to make better use of solar is to shift electricity use into the daytime when possible, such as running appliances or charging devices when solar power is available.
Another option is to use battery storage. Smaller plug-in batteries, typically around 1–2kWh and costing £500–£1,500, can store extra electricity for later use. However, because the amount of energy generated is quite small, the financial return on the battery is often limited, with payback periods of seven to ten years.
Daily savings can be estimated based on the difference between off-peak and peak electricity prices. In the UK, standard electricity prices are around 24–30p/kWh, according to Ofgem. This price difference means a small battery shifting around 1–2kWh per day could save roughly 25p–45p per day, equivalent to around £90–£160 per year. However, actual savings depend on usage patterns and seasonal variation.
Smart tariffs
A different approach is to combine battery storage with smart time-of-use tariffs. This technology, already established in the UK, allows batteries to be charged with cheaper off-peak electricity overnight from the grid and discharged during expensive peak periods.
One example already available is the EcoFlow Stream Ultra battery. A single unit can supply 250W–300W for appliances including fridges, routers and standby devices. It can discharge the power for approximately six to eight hours. In the future, a battery like this could potentially be charged from a solar panel.
To understand how this works in practice, consider a small battery of around 1.9kWh, costing approximately £1,500. If it is used only to store surplus solar energy from a balcony system, the financial return is relatively modest and will vary by season, with strong summer performance and lower winter output.
However, the savings change when the same system is used along with a smart time-of-use tariff. Instead of relying only on solar power, the battery can be charged overnight using cheaper electricity from the grid (typically 7–9p/kWh) and then used during the day when electricity is more expensive (often 30–35p/kWh). Typically, off-peak charges apply between midnight and 5am-6am.
This can lead to daily savings, usually around 25p–45p (up to around £1-£1.50 per day for larger batteries of around 5kWh), depending on usage and price differences. When these steady savings are combined with seasonal solar generation, total savings could reach £200-£300 per year.
This means the overall system could pay for itself in around five to six years. And for the larger battery systems, savings could be higher, reaching around £500–£650 per year.
Overall, solar will work best as part of a wider shift in households rethinking when and how to use energy.
Salma Al Arefi does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.