Best UPS for a router in the UK (2026)

The 4 types of router backup, compared

Almost everything sold as backup power for a router falls into one of 4 types. They are not equal: some won't power a UK hub at all, and some keep a computer happy but make a poor fit for a hallway.

Here is how the types compare on the things that matter for a UK broadband hub.

1. The right voltage: 12V

Most UK broadband hubs — BT, EE, Sky, TalkTalk, Plusnet, Vodafone and many Virgin Media models — run on 12V DC. Many cheap mini UPS units sold online output only 5V or 9V, because they were designed for small electronics, not UK hubs. Plug one of those into a 12V hub and it simply won't power it.

The check takes 10 seconds: look at the label on your hub's power plug. If it says 12V, a 12V backup like LineKeeper fits. If it says anything else, stop and check before you buy anything.

LineKeeper™ Hub Battery Backup

4+ hours of backup · fits in 60 seconds · free UK delivery · 90-day money-back

From £89

Choose your pack

2. Real runtime, measured in watt-hours

Battery size is the single biggest factor in how long your hub stays on. Look for the figure in watt-hours (Wh), not milliamp-hours (mAh). mAh figures are often quoted at a lower internal voltage, which makes the number look far bigger than the energy you actually get.

A typical UK hub draws roughly 10 to 15 watts. So a 74 Wh battery gives around 4+ hours, while a small 20 Wh mini UPS may manage little over an hour. For comparison, the backup solutions providers offer under Ofcom guidance only need to last 1 hour.

3. Instant, automatic switchover

This is the feature most people forget to check, and the one that matters most in a real power cut. If there's any gap between the mains failing and the battery taking over, the hub reboots. A reboot takes several minutes, drops any call in progress, and knocks every device off the Wi-Fi.

A good router UPS sits in line all the time and switches over in zero seconds, so the hub never notices the power went. Anything you have to plug in by hand — like a power bank — has already failed this test by the time you find the lead in the dark.

4. Silent running

A router backup lives in your lounge, hallway or bedroom, not a server cupboard. Office UPS units are built for desks and server rooms: many have cooling fans that hum constantly and beep loudly during every outage, sometimes for hours.

For a home, and especially an older person's home, look for a unit with no fan and no alarm beeps. A beeping box at 3am causes more distress than the power cut itself.

5. Fibre box support

Many full-fibre homes have a separate white Openreach box on the wall (the ONT) as well as the hub. Both need power for the internet and phone line to work. A backup with only one output leaves the job half done.

Check whether the unit can power both, either with 2 outputs or a splitter lead. LineKeeper includes a splitter lead in the box for exactly this reason.

6. Easy fitting and a real guarantee

The best router UPS needs no engineer, no app and no settings: you move the hub's power lead into the unit and plug the unit into the hub. If fitting needs tools or a manual the size of a novel, it's the wrong product for most homes.

Just as important is the guarantee. A proper money-back guarantee means you can test the unit with your own hub, in your own home, and send it back if it doesn't suit. LineKeeper comes with a 90-day money-back guarantee and free tracked UK delivery.

What to avoid

A few warning signs that a router backup will disappoint:

5V or 9V-only units — they won't power a UK 12V hub at all. No-name units with no UK support contact and no clear safety information. Units with no adapter tips, so the plug may not fit your hub's socket. Anything without automatic switchover, because the hub will reboot in the gap. And anything quoting battery size only in mAh, which usually hides a small battery.

What should it cost?

Honest price bands for the 4 types: basic 5V/9V mini UPS units run £20–£40 but rarely fit UK hubs; 12V mini UPS units run £30–£60 and quality varies widely; office UPS units run £60–£150 and are built for computers, not hallways; and a purpose-built hub battery backup like LineKeeper starts from £89 as a one-off purchase.

Worth comparing against the alternative: some providers offer backup for a monthly fee, which quietly adds up to far more than a one-off purchase over a couple of years.

The verdict: the best router UPS for most UK homes

For most UK homes, the best router UPS is a purpose-built 12V hub battery backup: right voltage, hours of runtime, zero-second switchover, silent, and able to power a fibre box too. LineKeeper meets every point on this list with a 74 Wh battery, adapter tips and a splitter lead in the box, and a 90-day money-back guarantee — which is why we make it.

In the spirit of honesty: if you need to power a desktop computer or a TV through outages, an office UPS is the right tool instead. And if your hub's plug label doesn't say 12V, check with us before ordering — we'd rather tell you now than after.

Checklist at a glance

Use this when comparing any router UPS.

How long will the backup last?

LineKeeper has a 74 Wh battery. A typical UK broadband hub uses roughly 10 to 15 watts, which gives 4 hours or more. Powering a separate fibre box as well, or an older hub that uses more power, shortens that. Fewer connected devices make it last longer.

For comparison, providers only have to offer a solution that lasts at least 1 hour. Many UK power cuts, especially in storms, last longer than that.

Is LineKeeper right for your home?

It's a good fit if: your phone now plugs into your broadband hub; someone at home relies on the landline or a pendant alarm; mobile signal is weak where you live; or you buy for a parent who lives alone.

It's not the right fit if: your hub's plug label doesn't say 12V; you need to power a computer, TV or fridge (LineKeeper is made only for hubs and fibre boxes); or your alarm already has its own mobile (SIM) connection and you don't use the landline.

Not sure? Try it for up to 90 days. If it doesn't suit you, send it back for a full refund.

How to fit it, step by step

1. Charge it. Plug LineKeeper into the mains and let it charge fully. It stays plugged in from then on.
2. Check the plug label. Look at the label on your hub's power plug. If it says 12V, LineKeeper fits.
3. Connect the hub. Unplug the hub's power lead from the hub, plug it into LineKeeper, then plug LineKeeper's output lead into the hub.
4. Add the fibre box if you have one. If a separate white Openreach box on the wall also has a power lead, use the splitter lead in the box to power both.
5. Plug in a corded phone. Keep 1 corded phone plugged into the hub's phone socket. Cordless bases need mains power, corded phones don't.
6. Test it. Switch the socket off at the wall. The hub lights should stay on and you should still get a dial tone.