If your desk has a desktop PC on it, buy the CyberPower CP1500PFCLCD: 1000W of real capacity, a true sine wave output that an active-PFC power supply will accept, and about ten minutes of runtime at half load — enough to save and shut down. If your desk is a laptop and a monitor, you do not need a battery at all; buy the Tripp Lite Isobar and spend the difference elsewhere. The laptop already has a UPS inside it.
The two devices are routinely treated as a good/better pair, and they are not. A surge protector defends against energy arrivingon the line — a spike from a lightning strike, a compressor kicking in, a utility switching event. A UPS defends against energy leaving— a blackout, a brownout, a half-second dip that reboots a PC. Most UPS units include some surge protection, but the amount varies wildly, and this page exists because the numbers are public.
The joules number, side by side
Surge capacity is published in joules: how much excess energy the device can absorb before it stops protecting. The Tripp Lite IBAR6-6D is rated 3,330 joules. The APC Back-UPS BE850G2 publishes 354 joulesof surge energy. That is not a typo and it is not unusual — a UPS spends its budget on a battery, a transformer and an inverter, not on a bank of metal-oxide varistors.
So “a UPS covers both” is only true if its surge rating is adequate for your situation. On a desk in an area with frequent storms, the honest arrangement is a UPS for the computer and a properly rated surge strip for everything else — which is how our power strip roundup ranks on joules in the first place.
Watts, not VA, is the number to size against
Every UPS carries two capacity figures. The VA number is bigger and gets printed larger; the watt number is the one your equipment actually consumes. The CP1500PFCLCD is 1500VA but 1000W. The ST425 is 425VA but 260W. Add up your real draw — a mid-range desktop and two monitors is commonly in the 250 to 450W region under load — and buy a unit whose watt rating has headroom above it, because runtime collapses as you approach the ceiling.
The published runtimes make that visible. The CP1500PFCLCD is rated 10 minutes at half load and 2.5 minutes at full load; the ST425 is 6 minutes and 1.5 minutes. A UPS is a save-and-shut-down device, not a way to keep working through an outage.
Waveform decides compatibility, not quality
A line-interactive UPS with a true sine wave output, like the CP1500PFCLCD, produces something close to mains. A cheaper standby unit produces a simulated sine wave— a stepped approximation. Active-PFC desktop power supplies, which is most of them now, can reject a simulated wave and either refuse to run or click loudly on transfer. That is why the budget pick on this page is recommended for a router and a laptop rather than a tower.
Battery-backed outlets are not all the outlets
Every UPS here splits its sockets. The CP1500PFCLCD has 12 outlets: six surge plus battery, six surge only. The BE850G2 has nine, split six and three. Plug the computer into a surge-only socket and you have a large, expensive surge protector. Label them on day one, and put the printer and the monitor chargers on the surge-only side where they belong.
Our battery backup roundup ranks the UPS side in full, and if the real problem is that your desk has one wall socket and nine plugs, that is a power strip question rather than a battery one.
The published numbers, side by side
| Device | Surge rating | Battery capacity | Runtime (half / full) | Waveform |
|---|
| CyberPower CP1500PFCLCD | Not published as joules | 1500VA / 1000W | 10 min / 2.5 min | Sine wave |
| Tripp Lite IBAR6-6D | 3,330 joules | None | — | — |
| APC Back-UPS BE850G2 | 354 joules | 850VA / 450W | Not published | Not published |
| Belkin 12-outlet | Not published | None | — | — |
| CyberPower ST425 | Not published as joules | 425VA / 260W | 6 min / 1.5 min | Simulated sine |
The gaps are the point. CyberPower publishes runtime and waveform but not a joule figure; APC publishes a joule figure but neither runtime nor waveform; Belkin publishes neither. Nobody on this page publishes everything, so the comparison is what each maker will actually stand behind.
Which one, in one line each
Laptop and a monitor: surge protector only. The laptop battery is already a UPS with a better runtime than anything here.
Desktop PC: a line-interactive sine-wave UPS sized in watts, plus the monitors on its surge-only outlets. This is the case the CP1500PFCLCD exists for.
Working from home on a flaky line: a small UPS behind the router and modem. If the network survives the dip, a laptop user never notices it.
Storm-prone area:both, deliberately — each on its own wall socket, with the peripherals on the high-joule strip and the computer on the UPS. The one arrangement every maker warns against is a UPS plugged into a surge protector or power strip, because the strip's clamping circuitry sits between the UPS and the mains it is trying to measure.
Four things people get wrong
Daisy-chaining. Strip into strip, or a UPS into a strip, is both a protection problem and a fire-code problem in most jurisdictions. A plain, non-surge strip on a UPS output is fine for low-draw peripherals; a second surge protector there is not.
Assuming a laser printer can go on the UPS. Its fuser draws a large inrush current and will overload a desk-sized unit. Printers go on the surge-only outlets.
Ignoring the end of life. Surge protection is consumed by use. The Isobar's protection LED exists so you know when the strip has become an extension cord; a strip without that light gives you no way to tell.
Forgetting the cables underneath.A UPS is heavy, the floor is where it lives, and a standing desk moves everything above it — standing desk cable management covers the slack a rising desk needs, and the under-desk roundup gets the rest off the carpet.
