If you’re tired of sending your hard-earned solar energy straight back to the grid, it might be time to keep that power where it belongs - in your home.
With solar panels booming across the UK (and energy prices showing no signs of mercy), battery storage has quickly become the next must-have upgrade for solar-savvy homeowners.
Enter Powervault 3 - a proudly British-built solar battery designed to cut your grid reliance, lower your bills, and give you total control over how you use your energy. It automatically stores your excess daytime solar power and dishes it back out after sunset, when electricity is at its priciest.
In this guide, we’ll unpack everything you need to know about the Powervault 3 - from real-world UK prices and installation costs to performance specs, pros and cons, and how it stacks up against big names like the Tesla Powerwall 3 and Alpha ESS G3.
By the end, you’ll see exactly where it fits in Heatable’s full solar + battery range, and why getting a quick quote could be the easiest way to start slashing your bills (and your carbon footprint).
PS We offer MCS-certified battery installation nationwide. Simply answer these questions, get your fixed price, and arrange your free design.
A Home-Grown Hero: The Powervault 3
Powervault is a proudly British company - founded in London, assembling in Luton, and driven by a simple goal: make energy storage smart, sustainable, and accessible for everyone.
With a laser focus on cutting carbon and costs, Powervault has even teamed up with the National Physical Laboratory to verify real-world CO₂ savings of over 300 kg per home, per year. That’s not just clever marketing - it’s measurable impact.
At its core, the Powervault 3 is a modular lithium-ion (Li-NMC) battery system that captures surplus solar energy (or cheap off-peak grid power) and feeds it back when you need it most.
Capacities range from 4 kWh - ideal for smaller setups - all the way up to 20 kWh, with the flexibility to add more storage later as your energy needs grow.
Each unit comes with a built-in solar inverter for easy retrofitting, a simple app for live monitoring and scheduling, and smart compatibility with both solar charging and grid top-ups.
For most UK homeowners, that means boosting solar self-consumption from roughly 30 % to over 70 %, dramatically cutting peak-time imports and bills.
And here’s the patriotic bonus: the entire system is designed, built, and supported right here in the UK - giving you faster service, local expertise, and zero import headaches compared with overseas rivals.
Powervault 3 Cost in the UK
When it comes to price, the Powervault 3 hits a sweet spot between premium performance and home-grown value. Costs vary by capacity, but it’s competitively priced considering its modular design and British build quality.
Expect to pay around £4,700–£5,000 for a 4 kWh unit (battery only), scaling up to roughly £14,000–£14,800 for the full 20 kWh setup.
Add £1,000–£1,500 for professional installation - covering wiring, inverter integration, and all-important G99 grid compliance - and your total outlay typically lands between £5,700 and £16,300, depending on your home and existing solar setup.
Extra factors such as three-phase wiring, outdoor installation, or retrofits can bump the price by 10–20%.
Here’s the good news - since April 2022, all solar + battery bundles qualify for 0 % VAT, saving you up to 20 % (over £1,000 on larger systems). And since February 2024, that same 0 % VAT break also applies to stand-alone battery installations.
While England and Wales currently don’t offer direct battery grants, Scotland’s Home Energy Scotland Loan provides up to £5,000 interest-free - worth checking out if you’re north of the border.
As for payback, most solar households can expect returns within 7–10 years, or even faster (5–7 years) when paired with smart tariffs.
Link your Powervault 3 to Octopus Flux (off-peak charging at 7 p/kWh) or Octopus Agile (dynamic hourly rates) to supercharge savings - storing cheap night-rate electricity and selling or using it during 30 p/kWh peaks can trim bills by £400–£600 per year.
And one final perk: through Powervault’s GridFLEX platform, you can earn around £120 a year for two years just for letting your battery support the national grid.
For easy comparison:
Capacity | Battery Cost (Excl. VAT) | Total Installed Cost | Estimated Annual Savings (with a 4kW Solar) |
4kWh | £4,700–£5,000 | £5,700–£6,500 | £300–£400 |
8kWh | £7,000–£7,500 | £8,000–£9,000 | £450–£550 |
12kWh | £9,500–£10,000 | £10,500–£11,500 | £550–£650 |
16kWh | £12,000–£12,500 | £13,000–£14,000 | £600–£700 |
20kWh | £14,000–£14,800 | £15,000–£16,500 | £650–£700 |
Prices are 2025 estimates; get a Heatable quote for tailored figures.
Powervault 3: Pros and Cons
Pros:
UK-made and supported – Designed, built, and serviced in Britain, meaning faster support and no overseas delays.
Modular capacity – Start with as little as 4 kWh and expand up to 20 kWh as your needs grow.
Smart tariff ready – Works seamlessly with flexible energy tariffs like Octopus Flux or EDF’s GoElectric, helping you charge cheap and use power when rates peak.
Strong warranty – Backed by a 10-year product warranty and a capacity guarantee of less than 30% degradation over its lifespan.
User-friendly app – Real-time monitoring and scheduling through an intuitive web portal and mobile interface.
Cons:
Higher upfront cost – Slightly more expensive than entry-level imported systems, though build quality and local support offset the premium.
Larger footprint – The 20 kWh model stands nearly 2 metres tall and is suitable for indoor installation only.
Backup not included – Off-grid or backup power during outages requires an additional module, typically adding £500–£1,000 to the setup cost.
Is the Powervault 3 Worth It?
In most cases, yes - especially if you’re a medium-to-large household (3–5 bedrooms) with a 4 kW+ solar array already pulling its weight.
The Powervault 3 really shines for eco-conscious families who want to make the most of their solar investment.
By storing excess daytime energy and using it in the evening, many households can cut grid reliance by around 70%.
Pair it with a time-of-use tariff, and it becomes a genuine bill-slayer. You can charge up overnight at low off-peak rates, discharge during high-price periods, and save £400–£700 per year without changing your habits.
A typical 10 kWh Powervault setup can comfortably cover most evening consumption in an average family home, dramatically reducing dependence on grid imports.
It’s also a smart pick for anyone who values British engineering, local support, and short supply chains - no long waits for parts or overseas servicing.
That said, it’s probably overkill for smaller properties (with under 2 kW of solar) or anyone chasing a full off-grid setup without add-ons. In those cases, a compact system like the Alpha ESS might be a better fit.
How It Compares to Other Solar Batteries
Curious how the Powervault 3 stacks up against the competition? Here’s a quick look at the leading contenders - all available through Heatable’s nationwide installation service.
For more detail, check out our dedicated guides on the Tesla Powerwall 3 and Alpha ESS G3.
Battery | Capacity Range | Warranty | Smart Charging | Backup Option | Best For |
Powervault 3 | 4-20 kWh | 10 years | Yes | Optional | UK support, modular design |
Tesla Powerwall 3 | 13.5 kWh | 10 years | Yes | Yes | Premium, all-in-one design |
Alpha ESS G3 | 5-13 kWh | 10 years | Yes | Yes | Balanced performance and value |
The Powervault 3 stands out for its flexibility, British engineering, and local support, making it ideal for homeowners who value reliability and scalability.
The Tesla Powerwall 3 leads on sleek design and seamless app control, while the Alpha ESS G3 remains the go-to choice for compact homes seeking strong performance at a lower price point.
Next Steps For Your Battery Journey:
When planning to install battery storage for your home, there are several important factors to consider. Make sure to refer to the following guides to help you make informed decisions:
To dive deeper into these topics, head over to our advice section, check out our YouTube channel for informative videos, or read a customer case study to see how others have benefited from their battery installation.
Get a Quote for a Battery Today
Without boasting you should get your battery storage installed with us, here's why:
Thousands of Happy Customers: We boast an average score of 4.9 on Trustpilot, outperforming the market leader.
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Bespoke Battery Quote Tool: Find out which battery is ideal for your home, here.
