Best Home Battery UK 2026: Tesla vs Fox ESS vs Sunsynk

There is no single best battery, but there are best-fit ones

Ask ten installers for the best home battery and you will get ten answers, usually whichever brand they resell. As an independent quote and comparison service we do not sell hardware, so this 2026 comparison is about matching the right battery to the right home, not crowning a winner. Below we compare the main UK brands on price, value, warranty and backup, then explain the one brand we deliberately leave off our buy list this year. Every price is a researched market estimate and your own quote will differ.

Before the table, a reminder on how to read it. Compare batteries on cost per usable kWh, not the headline price, and always separate warranty terms from marketing claims. A cheaper battery with a weaker warranty or a manufacturer in trouble is not the bargain it looks. Our cost guide explains the per-kWh method in full.

The 2026 comparison table

Brand and model	Approx cost	Rough £/kWh	Warranty and backup	Best for
Tesla Powerwall 3 (13.5 kWh)	~£5,600 supply + ~£1,750 install	~£414/kWh	10-yr unlimited-cycle; strong whole-home backup	Backup and high-usage homes
Tesla Powerwall 2 (13.5 kWh)	~£5,000 supply + ~£1,550 install	~£370/kWh	Well-proven; solid backup	Larger homes on a budget
Sunsynk (10 kWh)	£4,500 to £5,500	Best-value tier	Good hybrid inverter ecosystem	Mid-market value
Fox ESS (5 kWh)	from ~£5,600 installed	Mid	Modular, flexible sizing	Homes wanting to expand later
Alpha ESS G3	~£255/kWh supply + ~£1,400 install	Cheapest per kWh	Competitive	Tightest budgets
Pylontech / Growatt	Budget modular	Lowest	Basic	Cost-first modular builds
Enphase / SolarEdge	Premium	Higher	Optimised, panel-level control	Complex or shaded roofs
Sigenergy	Premium	Highest	AI all-in-one design	Premium, feature-led buyers

Tesla Powerwall 3: the backup and warranty leader

The Powerwall 3 is the battery to beat on two fronts: its 10-year unlimited-cycle warranty is unusually strong, and its backup performance is among the best for keeping a whole home running through a power cut. At around £414 per kWh supplied plus roughly £1,750 to install, it is not cheap, but for high-usage homes, or anyone who prioritises resilience with an EPS-style backup, it is often worth the premium. The older Powerwall 2 remains a sensible, cheaper alternative at around £370 per kWh if you can still source one. If backup matters to you, read our backup power and EPS page.

Sunsynk: the best-value mid-market choice

For most typical homes in the 3,000 to 4,500 kWh a year band, a Sunsynk 10 kWh system at £4,500 to £5,500 hits the sweet spot on value. The hybrid inverter ecosystem is well regarded, the pricing is keen, and 10 kWh is the capacity most UK homes actually need. If you want the most sensible balance of cost and capability without paying a premium badge, this is usually where we point people first. Our 10 kWh battery page covers this size in detail.

Fox ESS and Alpha ESS: modular and budget

Fox ESS offers solid modular batteries from around £5,600 installed for 5 kWh, which suits homes that want to start smaller and expand later. Alpha ESS G3 is the cheapest per usable kWh in this comparison at around £255 per kWh supplied, making it the value pick for the tightest budgets. Pylontech and Growatt sit in the same budget-modular territory. None of these are premium, but a well-installed budget battery on a strong tariff can pay back perfectly well, as our is it worth it guide explains.

Premium and specialist options

Enphase and SolarEdge are optimised systems with panel-level control, which earns its keep on complex or partially shaded roofs where a standard string setup would lose output. Sigenergy is a premium AI all-in-one aimed at feature-led buyers who want the newest integrated design. These carry a higher per-kWh cost and are worth it only if their specific strengths match your home.

Why we exclude GivEnergy from our buy picks in 2026

GivEnergy was, until recently, a major UK residential battery brand. We are not recommending a new GivEnergy system this year, and it is important to be clear why. GivEnergy Ltd entered administration on 9 April 2026, with staff made redundant and administrators appointed. Existing GivEnergy batteries keep working, but ongoing warranty support, firmware updates and spare parts are now in serious doubt, and a paid cloud tier has been announced.

For a buyer, a battery is a 10-year-plus purchase, and manufacturer stability is part of what you are buying. A brand in administration cannot reliably stand behind a decade-long warranty, so we treat GivEnergy as a cautionary example rather than a buy. If you already own one, do not panic, your battery still works, and we explain your options in what happened to GivEnergy. The wider lesson is to factor warranty security into brand choice, not just headline price.

AC-coupled or DC-coupled: it affects your shortlist

Which batteries suit you depends partly on whether you are retrofitting to existing solar or building a new system. A retrofit is usually AC-coupled, meaning the battery has its own inverter and bolts on alongside your existing setup, with round-trip efficiency around 90 to 92%. Many of the batteries above, including Sunsynk, Fox ESS and Alpha ESS, work well in this role. A brand-new solar-and-battery system can be DC-coupled, sharing a hybrid inverter for a higher 95 to 97% efficiency, which suits an all-in-one design. If you already have panels, prioritise a battery with a strong AC-coupled retrofit story; if you are starting fresh, a hybrid DC-coupled option may edge ahead. Our battery retrofit and solar and battery pages go into the difference.

Warranty terms: read past the headline

Cycle life and warranty length are where batteries genuinely differ, and they matter more than a small price gap. A quality lithium-iron-phosphate battery is typically warranted for around 6,000 to 10,000 cycles, or 10 to 12 years, holding roughly 70 to 80% of its capacity by the end and fading only about 1.5 to 3% a year. The Tesla Powerwall 3’s unlimited-cycle warranty is a genuine standout, because it means you are not penalised for cycling the battery hard every day to maximise savings, which is exactly what a well-used battery should do. When comparing two batteries at a similar price, the one with the longer warranty and higher retained capacity is usually the better long-term buy.

Do not choose on price alone

It is tempting to sort by cost per kWh and pick the cheapest, but the GivEnergy situation shows why that can backfire. The safest buy balances four things: cost per usable kWh, warranty length and cycle life, backup capability if you need it, and the financial stability of the manufacturer standing behind the warranty. A battery that wins on price but loses on warranty security is not a bargain over a decade. Because we are independent and do not resell hardware, we can weigh all four for your specific situation rather than steering you to a single stocked brand.

How to choose for your home

The right battery depends on your priorities:

• Want the strongest warranty and backup? Tesla Powerwall 3.
• Want the best all-round value? Sunsynk 10 kWh.
• On a tight budget? Alpha ESS or a budget modular brand, well installed.
• Complex or shaded roof? Enphase or SolarEdge optimised systems.
• Prioritise manufacturer stability? Choose a brand with a healthy balance sheet standing behind its warranty.

Whatever you lean towards, get more than one quote and compare on usable kWh and warranty terms. We match you to vetted, MCS-registered independent installers across brands, so you can compare like for like. Model your savings with our savings calculator, read the common questions in our FAQs, and start with our quote service when you are ready.