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Homelab · Guide · By Mohammed Almuhanna · Updated
Best UPS for a NAS or Homelab (2026)
I do not run a UPS. A UPS is way too expensive where I live, in Saudi Arabia, and the grid here is stable enough that I have never been bitten, so I made the call not to buy one yet. But I run an always-on homelab, a Synology on SHR-1 and a Proxmox box, so the stakes are real, and I built the UPS sizing calculator, so I know the math cold. If I were buying one for a NAS today the choice would be easy. A NAS needs a UPS for one job, to shut down cleanly before the power drops, so a sudden cut never corrupts the array mid-write. That points you at a specific kind of unit. Here is what actually matters, and the two I would buy.
The short version
Buy a line-interactive, pure sine wave UPS with a USB data port and a user-replaceable battery, sized so it carries your gear for 10 to 20 minutes. The value pick is the CyberPower CP1500PFCLCD. If you run Synology and want the unit DSM officially supports, get the APC Back-UPS Pro 1500. Skip simulated sine wave units. Do not chase hours of runtime you will never use.
What a NAS actually needs from a UPS
Most of the spec sheet does not matter for a home NAS. Four things do.
- Pure sine wave output. Modern NAS and server power supplies run active power factor correction. On a stepped or simulated sine wave, an active-PFC supply can buzz, or worse, drop the load at the exact moment the UPS switches to battery. A pure sine wave output avoids that. This is the one spec I would not compromise on.
- A USB data link. The whole point of the UPS is a graceful shutdown, and that only works if the NAS can hear the UPS. A USB connection lets Synology DSM, QNAP, TrueNAS, or Network UPS Tools watch the battery and shut the box down cleanly before it dies. A UPS with no data link only delays a shutdown you will not be awake to watch.
- A user-replaceable battery. UPS batteries wear out in three to five years. You want to swap a $30 battery, not bin the whole unit. Both picks below take replaceable batteries.
- Enough runtime to shut down, not to keep running. Ten to twenty minutes at your load is plenty. Runtime drives battery size and price, and it climbs steeply, so do not pay for hours you will not use. If you need to survive long blackouts, that is a generator, not a UPS.
Line-interactive units do all of this, and that is the right call for almost every homelab. Double-conversion online units are cleaner still, but they cost more and run hotter, so save them for genuinely critical gear.
UPS units worth buying
| Model | Rating | Waveform | Battery | Shutdown | Best for |
|---|---|---|---|---|---|
| CyberPower CP1500PFCLCD | 1500 VA / 1000 W | Pure sine | Replaceable | USB | Best value for most homelabs |
| APC Back-UPS Pro 1500 (BR1500MS2) | 1500 VA / 900 W | Pure sine | Replaceable | USB | Synology owners who want official support |
| CyberPower OL series (true online) | 1500 VA / 1350 W | Pure sine | Replaceable | USB | Critical gear that cannot see a transfer |
CyberPower CP1500PFCLCD (the value pick)
This is the one I would buy. 1500 VA / 1000 W, pure sine wave, a clear LCD readout, a user-replaceable battery, and a USB port that talks to NUT and to every major NAS OS. At its load it carries a typical 150 to 250 W homelab well past the 10 to 20 minutes you need for a clean shutdown. It usually costs noticeably less than the APC for the same feature set. The one catch is that Synology does not always list CyberPower on its official compatibility page, so if you want a name DSM explicitly blesses, get the APC below.
APC Back-UPS Pro 1500 (the safe Synology pick)
I do not own one, so I will not pretend otherwise. This is the unit I would point a Synology owner to who wants zero compatibility doubt. APC is on Synology's supported list, the DSM integration is well tested, and the brand has a long reliability record. Same essentials as the CyberPower, pure sine wave, USB shutdown, replaceable battery. You pay a bit more for the badge and the official support, and for a lot of people that is worth it.
When to step up to an online UPS
If you are protecting something that genuinely cannot tolerate even the brief switch to battery, a true double-conversion online unit, like CyberPower's OL series, runs the load off the inverter all the time, so there is no transfer to notice. Note that the line-interactive picks above are not online units, despite CyberPower's confusingly similar model names, so look for the OL prefix if online is what you actually need. For a normal home NAS this is more than you need. For sensitive or critical equipment it is the right answer.
Size it before you buy
The model is only half the decision. The other half is making sure it carries your load with margin. Add up the real running watts of everything the UPS will hold, then load the unit to about 50 to 80 percent of its watts rating, not 100. The UPS runtime and sizing calculator does this both ways. Enter your watts to see runtime, or set a runtime target to find the size you need. For the full walk-through, including why you size to watts and not VA, read what size UPS do I need.
Connect it, or it does nothing useful
Plug the UPS into the NAS over USB and turn on UPS support in the OS. On Synology that is Control Panel, Hardware and Power, UPS. On TrueNAS or a Linux box, NUT does the same job. Set it to shut the NAS down gracefully when the battery runs low. Skip that link and the UPS is just a noisy battery that runs out while you sleep, so do not skip it.
Common questions
Do I really need a UPS for my NAS?
If your grid is stable you can get away without one. I run mine without a UPS for that reason, plus a UPS is expensive where I live. But it is cheap insurance for most people. A single power cut during a write or a RAID rebuild can corrupt data or degrade the array. A UPS exists to shut the NAS down cleanly before that happens, not to keep it running through a long outage.
CyberPower or APC for a NAS?
Both are good, pure sine wave units with USB shutdown. CyberPower CP1500PFCLCD is the better value and works fine with NUT and every major NAS OS. APC Back-UPS Pro 1500 is the safer pick for Synology specifically, because Synology lists it as supported. Choose on price and on whether official Synology support matters to you.
How much runtime should a NAS UPS have?
Ten to twenty minutes at your load is plenty. The job is a clean shutdown, not running the rack for hours. Runtime drives battery size and cost and climbs steeply, so paying for more is usually wasted money. For long blackouts, use a generator.
Why does pure sine wave matter?
Modern NAS and server power supplies run active power factor correction, which can buzz or drop the load on a stepped or simulated sine wave when the UPS switches to battery. A pure sine wave output avoids that, which is why it is the one UPS spec I would not compromise on for a NAS.