Emergency Power Supply for Home: Which Category Fits a Three-Day Disruption?

The honest answer to what makes a good emergency power supply for home is that it depends on what must keep running, and for how long. Four categories are realistically available to UK households, and they solve different problems.

Be Ready, the Cabinet Office campaign published on 22 October 2026, asks households to prepare for three days of disruption. That means three days of supplies, not three days of electricity. Keep that distinction and a bargain like a plug in solar kit stops looking like backup.

What does an emergency power supply for home actually need to do?

Begin with loads, not products. A fridge, a router, a phone charger, a few LED lamps and a boiler pump sit at one end; an electric shower, an oven and a heat pump sit at the other. The gap between those lists decides your category more than any specification.

Rank that list before choosing hardware: continuous loads first, cycling loads second, anything that heats water or air last. Load priority decides whether a modest battery feels generous or useless, and it costs nothing to write down.

A plug in solar kit does not change that arithmetic. It has no battery, so there is nothing stored to draw on when the grid goes down.

Then decide duration. Official power cuts guidance describes a resilient system where most cuts are short and local, but warns that wider outages could last several days with regional or, although unlikely, national impacts. Three days is a planning assumption, not a forecast.

Finally, decide who may install what you buy, which removes some options outright.

What can the official Be Ready kit do on its own?

The Be Ready checklist costs little and covers more than people assume.

The baseline is the official one: three litres of drinking water per person per day, three days of no-cook food, a torch with spare cells, an FM radio (battery or wind-up) and a charged power bank, copies of documents, cash, medication, first aid, baby formula and pet food. What that package does not include is anything that generates or stores electricity for the home. There is no battery, no generator and no inverter on it, and no plug in solar kit appears either.

Its power content is a torch and a power bank, which defines the baseline. As a category the verdict is narrow: light, information and phone charging, and nothing that needs mains power.

That is not a criticism. Three days of supplies carries a household through the awkward middle of a disruption, as the campaign frames it. Every other category here tries to close the gap, and a plug in solar kit closes none of it.

What does a portable battery cover during a power cut?

A portable battery is what most people picture when they search for emergency power for home. It charges from the mains and small devices plug in.

What a portable battery can run

Phones, a laptop, a router, LED lamps, a small fan, a radio and some medical devices. A few hundred watt-hours will carry those modest loads through an evening.

Where a portable battery stops

Capacity is the ceiling. A fridge for three days sits far outside what a handheld unit stores, and it usually recharges from the mains, so day one is the last it begins full.

This is the same limit that catches a plug in solar kit. Those systems are grid-tied and shut down with the grid, so a plug in solar kit adds generation in normal operation and nothing in a cut.

A flat portable battery, left uncharged, produces nothing. So does a plug in solar panel on a dark winter evening.

Where does a generator fit, and what does it cost you?

A petrol or diesel generator is the only category here that can, in principle, run for days, because you can refuel it. That is why they stay popular with people who have lived through a long outage.

The costs are real, and most never appear on the price tag. A plug in solar kit cannot match that duration, because it stores nothing and generates nothing after dark, but it avoids the problems below.

Fuel, noise and carbon monoxide safety

A generator burns fuel, needs servicing and is loud enough to annoy a neighbouring garden. Carbon monoxide is the serious risk: never run one indoors, in an attached garage or under an open window, because the exhaust is invisible and can kill.

Fuel storage compounds it. Petrol degrades over time, and keeping large quantities at home is a fire risk insurers ask about. None of that applies to a plug in solar kit, but then a plug in solar kit offers no outage supply.

The honest verdict: capable of long duration, but only for households willing to keep a fuel routine they may never use.

What can a hardwired home battery with an off-grid port run?

This is the category that behaves most like a permanent emergency power supply for home. The Anker SOLIX Solarbank 4 E5000 Pro is fitted to a wall or in a garage, charges from solar and grid, and includes a dedicated off-grid port that stays live during a cut.

The Anker SOLIX UK product page sets out a switch to Off-Grid Mode within 10 ms, supplying up to 2,500W to loads on that port. Backup reaches only loads connected to the off-grid port; whole-house, three-phase and on-grid-port backup are not supported.

The arithmetic of 5,024Wh

The official Anker SOLIX datasheet lists 5,024Wh of rated energy. At a steady 500W that is roughly ten hours (5,024 divided by 500 is about 10); at 1,000W roughly five; at 2,500W roughly two, all illustrative before losses and any Backup Reserve.

So this is not three days of electricity. It is a fixed quantity you allocate deliberately: a fridge for a few hours, the router, lights, a phone. A plug in solar kit has no budget to allocate.

Two outputs get mixed up constantly. The off-grid port delivers 2,500W in outage mode; the 2,990W sometimes quoted is maximum AC bypass output in normal grid mode, where 2,500W of battery combines with up to 490W from the grid. It is not backup power, and a plug in solar inverter has no equivalent figure at all.

The hardwired category is the one that needs a trade. Under Part P of the Building Regulations 2010, a Part P-registered electrician installs the unit on a dedicated circuit with the Anker SOLIX Smart Meter Gen 2; plug-in connection, though designed into the hardware, is not permitted yet. Budget for that visit, and for the G98 notification your electrician files within 28 days.

What does a hardwired battery add beyond its price?

Price is the easiest number to read and the least useful alone, because an option that cannot do the job is not cheap. The hardwired category costs more up front than a portable unit, and it is the only one here that combines silence, no fuel and a defined set of backed-up circuits.

Noise and fuel separate the categories quickly. A generator is audible next door and consumes fuel; a home battery is silent and refuels from sun or grid. A plug in solar kit is silent too, but a plug in solar kit with no battery is empty when it matters.

Safety separates them further. A generator brings exhaust and fuel storage, a hardwired battery a fixed installation by a qualified electrician, and a portable battery the least capacity. A plug in solar kit brings almost no risk and almost no resilience.

The three settings that matter after installation

Backup Reserve holds back a minimum state of charge for outages; the product page illustrates 15%, so a battery that has cycled all day still has something left. Parallel support for one to five units lets stored energy grow with the load list, and Storm Guard Mode watches weather alerts and pre-charges ahead of forecast severe weather. That last feature is the one thing no plug in solar kit can imitate.

The unit is £1,699 at the time of writing, reduced from £2,129 and including 20% VAT. That buys 5,024Wh of storage, 2,500W on the off-grid port during an outage, four MPPT inputs for up to 5,000W of solar and a 10-year warranty. The installation itself is a separate conversation with a Part P-registered electrician, and a plug in solar kit needs no such visit because it has nothing to wire in.

Which option actually covers three days?

Judge each emergency power supply for home category against a three-day disruption, not a one-hour blip.

The verdict for each option

• Official Be Ready kit: three days of supplies and only hours of power. Free to assemble and the right foundation.
• Portable battery: a few hours of small loads. Strong for phones, routers and lighting; weak for refrigeration.
• Generator: days if refuelled and sited safely outdoors. Demands fuel discipline and carries carbon monoxide risk.
• Hardwired battery with an off-grid port: selected essential loads for hours per charge, then recharges from solar and grid. Silent and not whole-house.
• Plug in solar kit: generates during normal operation and provides nothing during a cut, so it is not an emergency category.

No single category covers three days of ordinary household electricity at ordinary consumption. Ofgem's 2026 typical domestic consumption value is 2,500 kWh a year for a standard single-rate meter, roughly 6.8 kWh a day, more than the battery holds before efficiency losses. Treat it as a benchmark, not your usage.

What the hardwired category does is let you choose which loads matter and cover those. Of the options here, the Solarbank 4 E5000 Pro home battery runs unattended once a Part P-registered electrician has installed it.

A plug in solar kit sits outside the comparison: it generates while the grid is up and stops when the grid fails, so it cannot be what you lean on in a cut. A plug in solar system with a battery is a different product with a different design brief, and even then the off-grid port is what decides which circuits survive.

Conclusion

The right emergency power supply for home is the category that matches your load list, your tolerance for fuel and noise, and your willingness to have the work done properly. Start with the free official kit, then add hardware only for the loads you have decided to protect.

Three days of supplies is achievable for almost every household. Three days of whole-house electricity is not something any product here delivers, and a plug in solar kit is not a substitute for any of them. In a real emergency, follow official guidance, defer to the emergency services and consult a qualified electrician.

If a silent, hardwired option on a dedicated off-grid port fits your plan, review the Anker SOLIX Solarbank 4 E5000 Pro specification and confirm installation requirements with a Part P-registered electrician.

Frequently Asked Questions

Is a plug in solar kit any use during a power cut?

No. A plug in solar kit is grid-tied, so it switches off when the grid fails rather than feeding energy back into the network. That means a plug in solar system generates in normal operation and supplies nothing in an outage. Only a battery with a dedicated off-grid port can carry loads in a cut.

How much backup does a 5,024Wh battery actually give?

Roughly ten hours at a steady 500W, five hours at 1,000W and two hours at 2,500W, based on the 5,024Wh figure in the official Anker SOLIX datasheet. These are illustrative sums before losses and any Backup Reserve. Unlike a plug in solar kit, the battery stores a fixed amount you allocate.

Can a generator run a whole house for three days?

A generator can run for days if it is refuelled and sited safely outdoors, but that is not the same as running a whole house. It must never run indoors or in an attached garage because of carbon monoxide risk. A plug in solar kit cannot run for days either, since it stores no energy.

Do I need an electrician to install a home battery?

Yes. It belongs in the hardwired category: a Part P-registered electrician fits it to a dedicated circuit under the Building Regulations 2010, with the Anker SOLIX Smart Meter Gen 2, and files the G98 notification. Plug-in connection is not permitted yet, despite plug-in-ready hardware.

What is the difference between the 2,500W and 2,990W figures?

Read the two output ratings by mode: 2,500W is what the off-grid port can supply during an outage, while 2,990W is the maximum AC bypass output in normal grid mode (up to 2,500W battery plus up to 490W grid). The larger figure says nothing about backup capacity.

Is a portable battery enough for an emergency electricity supply home setup?

For phones, a router, lighting and a radio, yes, for a few hours. For a fridge over three days, no. Portable units store a few hundred watt-hours and usually recharge from the mains, so an outage on day one leaves whatever charge you had, and a plug in solar kit leaves nothing at all.