EcoFlow STREAM 5000 vs Anker SOLIX Solarbank 4 Pro: Which 5 kWh Battery for a UK Home?

The EcoFlow STREAM 5000 costs £1,599 and the Anker SOLIX Solarbank 4 E5000 Pro costs £1,699, direct from each maker's UK store on 21 September 2026. Both are 5,024 Wh home batteries with 5,000 W of solar input. The EcoFlow has the higher output at 3,000 W; the Anker is the one that's in stock now. In the UK both have to be wired in by an electrician, because the plug-in solar rules exclude anything with a battery inside it.

We've covered each of them separately, in our STREAM 5000 review and our Solarbank 4 Pro review. This page is for the person who has narrowed it down to these two and wants to know what actually separates them.

STREAM 5000 vs Solarbank 4 Pro Prices, Checked 21 September 2026

These are the prices on each maker's own UK store on the day we checked. Both are discounts against a higher list price, the RRP each maker strikes through, and neither store says when its sale ends.

Both are also on Amazon UK, and both are sold there by the brand itself rather than a reseller: the STREAM 5000 by EcoFlow through the EcoFlow store on Amazon, and the Solarbank 4 Pro by Anker SOLIX through the Anker store on Amazon. When we looked on 21 September 2026, Amazon had each one at the maker's full list price, so buying direct was the cheaper route for both that day. Amazon quoted four to five weeks for the STREAM 5000 and three to four days for the Solarbank 4 Pro, which matches what the makers' own stores say.

Don't treat any of that as settled. Amazon changes prices without notice, both brands run their own sales, and EcoFlow has already cut the STREAM 5000's list price once since pre-orders opened, from £1,899 to £1,799. Open the Amazon listing and the maker's store side by side and check the latest price on each before you pay. If Amazon is level or cheaper when you look, its delivery and returns may suit you better for a 45 to 50 kg box.

Specs Side by Side

Everything in this table comes from the two UK product pages. Where the makers publish the same figure, that's because the products really are that close.

One gap on EcoFlow's side: its UK page doesn't name the battery chemistry. EcoFlow's own Amazon listing calls it an LFP battery, the same chemistry as the LiFePO4 battery Anker states. Anker's warranty line needs a second look too. Its spec table reads “15 Years; 10 Years” under “Product Lifespan and Warranty”, and the highlights say “15-year lifespan”, so we read it as a 10-year warranty. Ask for the warranty document from either brand before you spend this much.

Output, Charging and Backup Power

This is the clearest difference between them. The STREAM 5000 can push 3,000 W into the house and charge from the grid at 3,000 W. The Solarbank 4 Pro does 2,500 W both ways. A UK kettle on its own can draw close to 3,000 W, so that extra 500 W decides whether the battery covers it or the grid tops it up. Anker says its 2,500 W fills the battery from empty in under two hours, which is already quick enough for any overnight cheap-rate window.

Both ship throttled. Anker sets the Solarbank 4 Pro to 800 W, and to raise it you email Anker proof of installation from your electrician, after which it sends an unlock password for the full 2,500 W. EcoFlow says the STREAM 5000 starts in a plug-and-play mode limited to the local cap, with anything above that needing a registered electrician's assessment first. That 800W setting comes from the 800-watt limit on plug-in systems in Germany and much of Europe. It doesn't make either unit a plug-in device here.

On backup, neither is a whole-house system. Each has a separate outlet that stays live in a power cut, and only what's connected to that outlet keeps running. Anker rates its at 2,500 W with a 10 ms switchover, which it describes as a UPS function. EcoFlow rates its at 3,000 W and says it switches “immediately”, without publishing a time.

Expansion: 30 kWh or 90 kWh

EcoFlow wins the headline. Its approach is modular: one STREAM 5000 takes two Expansion Battery 5000 packs for 15 kWh of storage capacity, and its STREAM Gateway links six units into a 90 kWh, 18,000 W system. Anker stops at five BP5000 packs and 30 kWh on a single 2,500 W inverter. Additional batteries are an extra cost on both: EcoFlow's Expansion Battery 5000 was £1,299 on its own when we checked.

For most UK homes that's academic. Ofgem's typical household uses 2,700 kWh of electricity a year, about 7.4 kWh a day, so 5 or 10 kWh of storage is the realistic range, and at that size the two are £100 apart again: £2,898 for the EcoFlow with one expansion pack, £2,998 for the Anker. Bear in mind that an 18,000 W EcoFlow system is far beyond a G98 notification and would need a G99 application to your network operator before it was installed.

Not the STREAM Ultra or the Solarbank 2 Pro

Both names invite confusion with the smaller units that came before. The EcoFlow STREAM Ultra is a 1.92 kWh balcony-scale battery, and the STREAM Ultra X is 3.84 kWh with 2,000 W of solar input; EcoFlow's UK store had the Ultra X at £1,299 when we checked. The STREAM 5000 is a different class: more storage, two and a half times the solar input, and a stackable design. Our guide to every STREAM model sets the range out. On Anker's side the Solarbank 2 Pro was the balcony-scale unit, and Anker's UK store now leads with the Solarbank 4 Pro instead. None of them, large or small, can use the UK plug-in route, because every one has a battery in it.

Installing Either One in the UK

Neither can use the plug-in solar route that opened in Great Britain on 27 August 2026. That route excludes any device with battery storage inside it, whatever output it's set to. Our battery rules report sets out the wording, and the certification tracker lists the kits that can be plugged in.

Anker is the more thorough of the two on UK paperwork. Its page says the Solarbank 4 Pro must be installed by a Part P-registered electrician on a dedicated hardwired circuit with Anker's Smart Meter Gen 2, that your electrician notifies the network operator under G98 within 28 days, and it publishes the ENA type test reference, ANKER/19908/V1. It also says the unit is floor-standing only and can't be wall mounted.

EcoFlow's UK page says less. Its FAQ is clear that in the UK the STREAM 5000 has to be installed into the distribution box by a professional installer or electrician. But we searched the page text for G98, the ENA register and the word DNO and found none of them, and no type test reference. Jonathan Tracey hit the same gap with a pre-production unit, saying in his video that the G98 paperwork was a challenge because the unit wasn't in the ENA database yet. At 3,000 W the unit is inside the G98 limit, so the process should be the same as Anker's. Ask EcoFlow for the type test reference before you order, because your installer will want it for the notification. Our G98 notification guide explains who your operator is and what they need.

Whichever you choose, get the electrician's quote first. It depends on your consumer unit, the cable run and whether you want the backup outlet wired to anything, and it can easily be bigger than the gap between the two sticker prices.

Apps, Tariffs and Home Assistant

A 5 kWh battery earns its keep on a time-of-use tariff, filling up when electricity is cheap and running the house when it's dear, so the software matters as much as the hardware.

Anker offers a time-of-use mode and a dynamic tariff mode that follows day-ahead prices, and says it's compatible with Octopus and more than 870 electricity suppliers. It supports two charge and discharge cycles a day, one from cheap overnight power and one from solar. Home Assistant integration is listed as supported today, which will settle it for anyone who runs their own automation.

EcoFlow's equivalent is OASIS 3.0, run from the EcoFlow app, with schedules built around tariff rates, solar input and weather forecasts. Its page says Home Assistant isn't supported yet, though it's planned. EcoFlow does have a Local Mode that keeps everything on your home network, but its own footnote says dynamic tariff integration, solar forecasting and firmware updates all stop working in that mode, so you'd be trading the clever features for privacy.

Both rely on a smart meter clamp at the consumer unit to see what the house is drawing, and when we checked both makers were including one at the sale price. EcoFlow's £1,599 bundle listed a Smart Meter Dual CT, which is £159 on its own. Anker's page listed the Smart Meter Gen 2 in the box as a free gift, and its installation terms require one. Offers like that come and go, and an Amazon listing may not match the maker's own store, so check what's in the box wherever you buy.

The Savings Claims: £770 and £1,506

Both makers put a big annual saving on the page, and both come from their own modelling.

Anker's “up to £770” is £769.82 in the footnote: £423.80 from using your own solar at 26p per kWh, plus £346.02 from charging overnight at 8.5p on a tariff like Octopus Go and discharging at 29.37p. It assumes a £2,510 setup with four 500 W panels, a household using 4,100 kWh a year, and one full cycle every day. The 3.3 year payback is worked out on that £2,510, and Anker's footnote says installation costs aren't included.

EcoFlow's “£1,506 per year” is further from a single STREAM 5000. Its footnote values every self-consumed unit at 30p per kWh, which is above the 26.32p Ofgem cap rate from October 2026, and the worked example it gives is a household using 7,000 kWh a year with two main units, two expansion batteries and 8,000 W of panels.

Neither figure is wrong as arithmetic, and neither is a forecast for your house. We have no independent number for either product. The savings calculator will model the solar half for your own postcode; the tariff half depends on rates only your supplier can give you.

Hands-On Videos from UK Reviewers

We haven't had either unit in our hands, so these are the videos we'd watch before spending this much. All are from UK channels dealing with UK wiring rules and tariffs. Bear in mind that review units are often supplied by the maker: eFIXX, Nicolas Raimo and Jonathan Tracey each say so on camera, as does UpsideDownFork in his Anker video.

EcoFlow STREAM 5000: tested on a meter

This is the most useful independent data on either product so far. UpsideDownFork tested the STREAM AC 5000, the version without solar inputs, with a plug-in energy meter. Running off-grid it boiled a kettle at about 2.37 kW without complaint. Charging from empty at 2 kW took about three hours and 5.9 kWh, and it gave back 4.92 kWh at an 800 W discharge, which he works out as 83.3% round trip. At a gentler 300 W discharge it returned 4.48 kWh, about 76%, because an inverter is less efficient well below its rating. Standby draw settled at around 11 W, the heat sink reached about 53 degrees C while charging, and a quiet internal fan was audible in a silent room.

What that means for a buyer: the rated 5 kWh is really there, but if the battery spends the day trickling a few hundred watts into the house you should expect nearer 4.5 kWh of it back. Those are one reviewer's measurements of one unit. EcoFlow rates the AC 5000 at 2,500 W to the house on its own, against the STREAM 5000's 3,000 W, so don't read the kettle test across directly.

Anker Solarbank 4 Pro: a real UK installation

eFIXX, a channel made for electricians, fitted one of the first UK units in a retired electrician's garage on a dedicated circuit. Their reason for hardwiring is the one in our table: wired in, the output goes from 800 W to 2,500 W. The practical lessons are worth more than the unboxing. The 60 V limit on each MPPT input meant one 440 W solar panel per input, so four panels needed four cable runs from the roof, and they used two four-core PV cables to keep it tidy. Mounting the panels was the hardest part of the job, and the ballasted mounting system cost more than the panels did. The smart meter sits by the consumer unit with a clamp on the meter tails and talks to the battery wirelessly, so you need Wi-Fi where the battery lives.

That 60 V point applies to the STREAM 5000 as well, since EcoFlow lists the same maximum. Neither unit lets you wire typical panels in series the way a rooftop inverter does. To get beyond four panels you parallel them with adapter cables, which is how both makers reach their 12-panel figure.

More worth watching

• EcoFlow Stream AC 5000: UK Rules & Setup Guide, Nicolas Raimo. The clearest explanation of the difference between the STREAM 5000 and the AC 5000, and of why either one goes on its own circuit with a G98 notification in the UK rather than into a socket.
• Anker Solix Solar Bank 4 Pro: The 5kWh Plug-in ready Battery you've Been Waiting For?, UpsideDownFork. Part one of three: unboxing, ports and the smart meter. His unit arrived with a three-pin lead as well as the hardwire connector, and he says plainly that in the UK it has to be hardwired today. His efficiency test of the Anker hadn't been published when we checked.
• Anker SOLIX Solarbank 4 Pro: Is This the BEST Plug-In Ready Battery Yet?, Jonathan Tracey. A 28-minute review, including the G98 notification and a walk through Anker's official Home Assistant integration over Modbus TCP.
• EcoFlow AC 5000 Review | UK First Look at the New 5kWh Home Battery, Jonathan Tracey. A first look at a pre-production AC 5000. He mentions that the G98 paperwork was a challenge at that point because the unit wasn't in the ENA database yet.
• Anker SOLIX Solarbank 4 E5000 Pro | Installation Guide (UK Version), Anker SOLIX Guides. Anker's own 11-minute guide: wall brackets, stacking expansion batteries, wiring 4, 8 or 12 panels, and the hardwire connector. Worth sending to your electrician.

One thing to watch for across these videos: some reviewers connect their unit to an existing fused spur, while Anker's UK instructions call for a dedicated hardwired circuit. Follow the maker's instructions and your own electrician over any YouTube install.

Which One Should You Buy?

• Buy the STREAM 5000 if you want the higher 3,000 W output and charging, you might expand past 30 kWh one day, and you're happy to wait until late October for it. It's £100 cheaper and a little lighter, at 45.4 kg against 50 kg.
• Buy the Solarbank 4 Pro if you want it soon, you use Home Assistant, or you'd rather hand your electrician a product whose UK paperwork is already published. It also has the better weather rating, IP66 against IP65.
• Buy neither if you rent, live in a flat, or can't have a hardwired installation. A verified plug-in kit from the tracker costs about a third as much and is the product the new law was written for.

If you're still torn, let the price decide on the day. The hardware is close enough that a £200 swing on either side is a fair reason to pick one over the other.

Where to Buy, and Checking the Latest Price

Each product is sold in two places that matter: the maker's own UK store and the maker's own Amazon UK listing. On 21 September 2026 direct was cheaper for both, by £200 on the EcoFlow and £430 on the Anker. Check all four links below before you order, because that gap can close or reverse at any time.

For the wider ranges, including expansion batteries, panels and smart meters, see the EcoFlow store on Amazon UK and the Anker store on Amazon UK.

Frequently Asked Questions