# The best UPS for a NAS is not the biggest one. It is the one that talks to it > The best UPS for NAS and home server setups is the one with pure sine output and a USB shutdown link, not the biggest. Our picks run from about $90 to $300. - Published: 2026-10-09 - Topic: [Computing](https://futuretechnologyhq.com/topic/computing/) - URL: https://futuretechnologyhq.com/article/best-ups-for-nas-home-server/ - Publisher: [Future Technology](https://futuretechnologyhq.com/), free to read. Quote as "Future Technology" with a link to the article. ## Key points - A UPS for a NAS has one job: keep the box alive for the five to ten minutes it needs to shut down cleanly. Runtime beyond that is a bonus, not the point. - Pure sine wave output matters for NAS units and mini PCs with active PFC power supplies, which can drop out on the stepped waveform cheaper units produce on battery. - The USB data cable is the most important accessory in the box. Without it, your NAS never knows the power went and the UPS just delays the crash. - For most homelabs the CyberPower CP1500PFCLCD (or its 230V twin) is the safe pick; a 600VA APC Back-UPS covers a two-bay NAS and a router for much less. ## Article *This article contains affiliate links. We may earn a small commission if you make a purchase, at no extra cost to you.* *Last updated: 9 October 2026* A power cut does not usually kill a NAS. The write it was halfway through does. A RAID array caught mid-write can come back needing a multi-hour resync, a ZFS pool can come back fine but grumpy, and a cheap SSD cache can come back with corrupted metadata. The fix costs less than one hard drive: an uninterruptible power supply that keeps the box alive long enough to shut itself down. Most people shopping for the best UPS for a NAS look at the wrong number. They compare VA ratings and runtime charts. The two things that actually decide whether your data survives are the waveform it puts out on battery, and whether it can tell your NAS the power has gone. ## What a UPS for a NAS actually needs to do Forget riding out a two-hour blackout. A typical four-bay NAS with spinning drives pulls somewhere around 40 to 60 watts. A mini PC running Proxmox or Home Assistant sits closer to 10 to 30 watts. Even a small UPS can hold that for 15 minutes or more. SpeedTestHQ's testing table puts the APC BX1500M at roughly 30 minutes at an 80 watt load. What you need is five to ten minutes, a signal, and a clean shutdown. The sequence goes: 1. Mains drops. The UPS switches to battery in a few milliseconds. 2. The UPS tells the NAS over USB that it is on battery. 3. The NAS waits a set time (two minutes is sensible, so brief flickers do not trigger anything), then stops services and powers off. 4. Power returns, the UPS recharges, and the NAS boots back up if you enabled "restore on AC power". Skip step 2 and the UPS only delays the crash. That is why the cable in the box matters more than an extra 500VA. ## Pure sine wave vs simulated sine on battery On battery, a UPS has to fake mains electricity. Cheaper line-interactive units produce a stepped approximation, a blocky wave with square corners. Pricier ones produce a smooth pure sine wave. Most modern NAS units, mini PCs and gaming PCs use power supplies with active power factor correction (active PFC). Some of those PSUs object to the stepped waveform. The worst case is ugly: the PSU drops out at the exact moment the UPS switches to battery, which is the one moment you bought it for. Plenty of people run simulated sine units on Synology boxes for years with zero problems, and WunderTech reports exactly that with APC's cheaper models. So here is my rule. If the pure sine version costs $50 or less extra, buy it. If you are protecting a low-power two-bay NAS and a router on a tight budget, simulated sine is a reasonable gamble. ## How to size a UPS for a home server VA is the headline number on the box. Watts is the one that matters. A 1500VA unit might be rated for 865, 900 or 1000 watts depending on the model and region, and those are the figures you size against. - Add up the real draw of everything on battery outlets: NAS, server, router, ONT or modem, switch. A cheap plug-in power meter tells you the truth in a day. - Keep that total under about 70% of the UPS watt rating, so it is not running flat out on battery. - Do not plug in a monitor, printer or space heater. Laser printers in particular pull huge spikes. For a single NAS plus networking, 600 to 900VA is enough. For a NAS, a server and a switch, go 1500VA. ### 120V vs 230V models UPS units are region-specific. North America and parts of Latin America use 120V models with NEMA outlets, Japan runs at 100V, and the UK, Europe, India, Australia and most of Asia and Africa need 230V models with local or IEC sockets. The same product line usually exists in both, under slightly different model numbers. Both are listed below where they exist. ## The best UPS for NAS and home server setups Prices below are rough US street prices as of October 2026. Expect similar numbers in pounds or euros once VAT is in. ### Best overall: CyberPower CP1500PFCLCD 1500VA and 1000W of pure sine wave output, according to retailer spec listings, for roughly $240 to $310. SHI lists two 9Ah batteries, about 10 minutes at half load, and a 4ms transfer time. At a typical 60 to 100 watt homelab load you get far more than 10 minutes. The USB port shows up as a standard HID power device, which is what Synology DSM, TrueNAS and Network UPS Tools on Linux all expect. The 230V version for the UK, Europe and Australia is sold as the CP1500EPFCLCD, rated at a slightly lower wattage. If you only buy one UPS, buy this one. [Check price on Amazon (US)](https://www.amazon.com/s?k=CyberPower+CP1500PFCLCD&tag=futuretech0d6-21) [Check price on Amazon (UK, 230V)](https://www.amazon.co.uk/s?k=CyberPower+CP1500EPFCLCD&tag=futuretech0d6-21) ### Best APC pure sine: APC Back-UPS Pro 1500 The North American BR1500MS2 is 1500VA and 900W, pure sine, with 10 outlets (six on battery, four surge-only) plus USB-A and USB-C charging ports on the front. The spec sheet lists a user-replaceable APCRBC163 battery, which matters in year four. In 230V markets the equivalent is the BR1500GI. It costs more than the CyberPower for similar output. Buy it if you already run APC kit or want APC's service network where you live. [Check price on Amazon (US)](https://www.amazon.com/s?k=APC+BR1500MS2&tag=futuretech0d6-21) [Check price on Amazon (UK, 230V)](https://www.amazon.co.uk/s?k=APC+BR1500GI&tag=futuretech0d6-21) ### Best mid-size pick: CyberPower CP850PFCLCD Same pure sine design as the 1500, smaller battery, listed at around $170. It is the sweet spot for a four-bay NAS, a router and a switch. [Check price on Amazon](https://www.amazon.com/s?k=CyberPower+CP850PFCLCD&tag=futuretech0d6-21) ### Best budget UPS for a two-bay NAS and router: APC BE600M1 600VA and 330W in a small floor unit, usually under $100. It uses simulated sine on battery, so read the section above before you buy. For a low-power two-bay NAS plus your router and ONT, it is the cheapest way to get clean shutdowns. It is also a solid answer if you want the best UPS for a WiFi router: your broadband stays up through short cuts, as long as the street cabinet does too. [Check price on Amazon](https://www.amazon.com/s?k=APC+BE600M1&tag=futuretech0d6-21) ### Best quiet 230V option: Eaton 5E Gen2 Eaton's refreshed 5E line covers 550 to 2200VA, and it is fanless up to 1200VA, which makes it the one to put in a living room or bedroom cupboard. The 900VA model is rated at 480W. The USB port is HID-compatible, and Synology owners report the 700VA unit being detected on DSM 7.2 even before it appeared on Synology's compatibility list. Eaton does not market it as pure sine, so treat it as a simulated sine unit. [Check price on Amazon (UK)](https://www.amazon.co.uk/s?k=Eaton+5E+Gen2+900&tag=futuretech0d6-21) ## Setting up automatic shutdown Plug the USB cable into the NAS, then: - **Synology DSM:** Control Panel, Hardware & Power, UPS. Enable UPS support, set the time before safe mode to a couple of minutes, and tick "Enable network UPS server" if other machines need the signal too. - **TrueNAS:** System Settings, Services, UPS. Pick the usbhid-ups driver and set a shutdown timer. - **Proxmox or any Linux box:** install Network UPS Tools (`apt install nut`), use the `usbhid-ups` driver, and point other machines at it as NUT clients. Then test it. Pull the plug at the wall while nothing important is writing, and watch. If the NAS does not shut itself down, you found out on your terms. If you are still choosing the box to protect, our guide to the [best home server OS](/article/best-home-server-os-2026/) covers TrueNAS, Unraid and Proxmox, and the [NAS vs cloud storage five-year cost breakdown](/article/nas-vs-cloud-storage-5-year-cost/) shows when owning the hardware pays off. ## FAQ ### Which UPS is best for home use? For a mixed home setup with a NAS, a router and maybe a small server, a 1500VA pure sine unit like the CyberPower CP1500PFCLCD covers everything. If it is just networking and a two-bay NAS, a 600VA unit is enough. ### Does a UPS replace backups? No. A UPS protects against power cuts. It does nothing for a dead drive, ransomware or a deleted folder. You still want the [3-2-1 backup rule](/article/3-2-1-backup-rule-how-to/), especially if you self-host something irreplaceable like your [photo library in Immich](/article/self-host-photos-immich-guide/). ### How often do UPS batteries need replacing? The sealed lead-acid batteries in home units typically last three to five years, less in a hot cupboard. Most units beep and flag a failed self-test when the battery is going. Buy a model with a user-replaceable battery and you can swap it in five minutes instead of binning the whole thing. ### Should my router be on the UPS? Yes, if you want remote access or notifications during a cut. Your router and ONT draw very little. Just remember the cabinet down the street may lose power too. ## The short version Buy pure sine if the price gap is small. Size it in watts, not VA, and stay under 70% load. Plug in the USB cable, configure the shutdown, and test it by pulling the plug. A $170 box that does those things will protect your data better than a $400 one that never talks to your NAS. ## Sources - [CyberPower CP1500PFCLCD listing via SHI](https://www.shi.com/product/22053913/CyberPower-PFC-Sinewave-Series-CP1500PFCLCD) - [APC BR1500MS2 spec sheet](https://content.abt.com/documents/158109/apc-surge-protector-BR1500MS2-spec-sheet.pdf) - [Eaton 5E Gen2 launch](https://www.electronicspecifier.com/products/power/eaton-launches-5e-gen2/) - [NUT usbhid-ups driver documentation](https://manpages.debian.org/jessie/nut-server/usbhid-ups.8.en.html) - [WunderTech on Synology UPS units](https://www.wundertech.net/best-synology-nas-ups-devices/) - [SpeedTestHQ NAS UPS runtime table](https://speedtesthq.com/best/best-ups-for-nas)