How much can solar save you? A balanced look at the numbers
You'll often see a figure like £800 to £1,100 a year quoted for what a typical home solar system can save. That range comes from the Energy Saving Trust for a roughly 4 kW system, and it's a reasonable starting point. But savings genuinely vary from home to home, so this article explains where the number comes from and what makes it go up or down.
Where the savings come from
Solar saves money in two ways. First, every unit of electricity your panels generate and you use at home is a unit you don't buy from your supplier. With electricity at the current cap rate of around 26p per unit, each self-used unit is worth that much.
Second, any surplus you export to the grid can earn a payment under a Smart Export Guarantee tariff. Export rates vary by supplier, currently ranging from around 15p to 25p per unit on the higher-paying deals. Using the electricity yourself is worth more than exporting it, which is why daytime use matters.
What moves the numbers
The size of your saving depends on a handful of practical factors, none of them mysterious:
- System size and roof space. A larger array generates more, but only if your roof has the room and orientation for it.
- How much you're home during the day. Using power while the panels are producing captures the most value.
- Roof direction and shading. South-facing with little shade is ideal, though east-west roofs work too.
- Your household's total usage. Higher usage means more of the generation can be absorbed at home.
- Whether you add a battery. Storage shifts daytime surplus to the evening, raising the share you use yourself.
A note on realism: these are typical ranges, not guarantees. Two identical houses with different daytime habits can see noticeably different savings, which is why a survey that looks at your actual usage is more useful than a headline figure.
Thinking about payback calmly
A typical 4 kW system costs in the region of £7,600 installed, according to the Energy Saving Trust, with prices varying by equipment and roof. Against annual savings in the £800–£1,100 range, many households see the system pay for itself over a number of years, after which the electricity it produces effectively costs nothing.
Panels typically keep producing for decades, so the longer you stay in the home, the more of the benefit you capture. If you're likely to move within a couple of years, it's worth factoring that in, though solar can also add to a property's appeal.
The takeaway: solar isn't a get-rich-quick scheme, but for many homes it's a steady, sensible way to reduce the part of the bill that keeps changing. The honest way to find out your figure is to look at your roof and your bills together.
We'd be glad to run through your numbers with no obligation. And if you'd like more context, our next piece looks at how much sunshine this coast actually gets across the seasons.