Best UPS (battery backup) for your network

A UPS keeps your modem, router and NAS alive through brief outages and brownouts — so your internet doesn't blink, and your NAS never loses power mid-write. Here's how to size one, and the units we'd actually plug in, in three tiers.

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Bargain get-it-done · Intermediate prosumer / IT generalist · Pro daily-driver for techs

What to look for

A UPS is a battery that sits between the wall and your gear. When utility power dips or drops, it carries the load instantly — long enough to ride out a momentary outage, or to shut a NAS down cleanly so it never corrupts a volume mid-write. Two things to get right: enough capacity, and a clean enough waveform for your hardware.

Sizing VA and watts for your load. Add up the draw of your router, modem, NAS or PC, then buy a UPS rated comfortably above it. A small unit holds a router and modem for a while; a NAS or desktop needs a bigger one. More headroom means more runtime.

Waveform Pure sine wave for a NAS or PC. Active-PFC power supplies in a NAS or desktop can stutter or shut off on the "stepped" output of cheap units. Pure sine wave output is clean enough for any PSU — worth it the moment a NAS or PC is on the UPS.

Protection AVR (automatic voltage regulation). AVR corrects sustained brownouts and surges without burning battery, smoothing dirty mains so your gear sees steady voltage and the battery lasts longer.

Runtime Enough runtime for your goal. Most outages are seconds. Decide whether you want to ride them out, or just buy time to shut down gracefully — that target sets how many VA you need.

Monitoring USB monitoring + auto-shutdown. A USB cable lets a NAS or PC watch the UPS and shut itself down on low battery — Synology speaks UPS natively, and Linux boxes use NUT. This is what turns a battery into real protection against data loss.

Bargain — small UPS for router + modem

The cheapest way to stop your internet blinking out. A small APC Back-UPS or CyberPower unit carries a router and modem through the short outages that make up most of them — and adds surge protection while it's at it. Perfect for a simple setup with no NAS.

Bargain APC Back-UPS / CyberPower (small) — keeps a router + modem online through brief outages, surge protection included. Find it →

Intermediate — pure sine wave + AVR ~1500VA

The right unit the moment a NAS or PC is involved. A ~1500VA pure sine wave UPS with AVR — the CyberPower CP1500PFCLCD is the perennial favorite — feeds clean power to PFC supplies, regulates brownouts, and has the capacity to run a router, modem and NAS together with USB auto-shutdown.

Intermediate CyberPower CP1500PFCLCD / APC (~1500VA, pure sine) — pure sine wave, AVR, USB monitoring; ideal for a NAS or desktop. Find it →

Pro — rackmount / Smart-UPS

When the gear lives in a rack and downtime isn't an option. APC Smart-UPS and CyberPower OR-series rackmount units bring more capacity, longer runtime, network management cards, and clean integration with shutdown software across a whole rack of equipment. Pair with monitored PDUs for a real closet.

Pro APC Smart-UPS · CyberPower OR (rackmount) — more capacity and runtime, network management, rack-ready. Find it →

A UPS rides out the outage. Acutis tells you it happened.

Battery backup keeps your gear alive — but you still want to know when the power blinked, when the internet actually dropped, or when a device fell off the network. Acutis Go is free and tells you in 60 seconds whether a problem is the Wi-Fi, the network, DNS, or your own device — and alerts you when the network drops, so an outage isn't something you discover hours later.

Download Acutis Go — free

Frequently asked questions

What size UPS do I need for a home network?

Add up the wattage of everything you'll plug in. A router and modem alone usually draw 20–40W, so a small 600–850VA unit runs them comfortably. Add a NAS or desktop and you want roughly 1500VA with a pure sine wave output. Always buy a size above your total load so you have runtime headroom.

How long will a UPS keep my router and modem online?

Because a router and modem draw so little, a small 600–850VA UPS typically holds them for one to three hours or more — enough to ride out the brief outages that make up the majority of them. Add a power-hungry NAS or PC and runtime drops to minutes, which is why those get a larger unit.

Do I need a pure sine wave UPS?

For just a router and modem, no — a simulated (stepped) sine wave unit is fine and cheaper. The moment a NAS or desktop is on the UPS, yes: their active-PFC power supplies can stutter, click, or shut off on stepped output, so pure sine wave is worth it.

What's the difference between VA and watts on a UPS?

VA is apparent power and watts is real, usable power; watts equal VA times the power factor. Older units run around 0.6, modern PFC-rated units near 1.0. Sizing on VA alone can leave you short, so check the watt rating against your actual load.

Will a UPS protect against surges and brownouts?

Yes. Every UPS includes surge protection, and models with AVR (automatic voltage regulation) correct sustained brownouts and overvoltage without draining the battery — which also makes the battery last longer on dirty mains.

Can a UPS shut my NAS down automatically?

Yes, over a USB cable. Synology and QNAP read a connected UPS natively, Linux uses NUT, and Windows uses the vendor app (PowerChute or PowerPanel). Auto-shutdown on low battery is what prevents a NAS from corrupting a volume mid-write during a real outage.

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