TL;DR: Choose a UPS by Watts (not just VA) with 30–50% headroom, keep only essentials on battery, and expect 10–30 minutes for safe saves/shutdown. Power the router/ONT too so Zoom/Teams keep working.

What you actually need to keep on

Laptop + charger (45–65 W typical; gaming 120–180 W under load)
Desktop PC (100–150 W idle, 300–500 W under load)
24″ monitor (20–30 W)
Router + ONT (8–15 W total)

If your goal is to finish an upload or exam, keep laptop + router powered. For desktops, plan enough time to save and shut down cleanly.

Sizing rules (no maths degree required)

Sum the Watts of what you’ll plug into the battery sockets.
Headroom: multiply by 1.3–1.5. That’s your minimum UPS Watt rating.
VA vs W: manufacturers list VA / W (e.g., 1500 VA / 900 W). Always match to W.
Runtime target: 10–30 min is enough for safe shutdowns and short calls. Longer needs a bigger battery (or fewer devices).

Example runtimes (typical consumer UPS classes)

Real runtimes vary by brand, battery size/age, temperature and inverter efficiency. Treat these as ballparks.

Load (what you power)	650 VA / ~360 W (1×7 Ah)	1000 VA / ~600 W (2×7 Ah)	1500 VA / ~900 W (2×9 Ah)
Laptop 45 W + router 10 W ≈ 55 W	45–70 min	90–120 min	110–150 min
Laptop 65 W + monitor 25 W ≈ 90 W	25–40 min	60–90 min	80–110 min
Desktop idle 150 W + monitor 25 W ≈ 175 W	10–18 min	28–45 min	40–65 min
Desktop 300 W (light load)	6–10 min	18–30 min	28–45 min
Desktop 400 W (heavier)	— (over many 650 VA W limits)	8–15 min	15–25 min

Tip: For desktops, a 1000–1500 VA class makes sense. For laptops, even a 650 VA can give you an hour if you only power the router + laptop.

Safe setup & shutdown (do this once)

Battery vs surge sockets: only essential gear on the battery side. Printers/lamps → surge-only.
USB cable to PC: install the UPS app so Windows/macOS can auto-save and shut down at, say, 5–10 minutes remaining.
Protect the network path: if possible, use a surge-protected Ethernet or keep the ONT + router on the UPS to avoid dropouts.
Test day one: pull the plug for 2–3 minutes and watch the system behave. Adjust timings as needed.

Need help configuring it? Book a Remote support session.

When a UPS pays for itself

Exams/interviews & billable calls (keep Zoom/Teams stable)
Avoiding file corruption during save/update/install
Routers/ONTs that drop power during short dips
Desktops with HDDs (graceful shutdown prevents filesystem repairs later)

Pair it with a quarterly check so batteries don’t silently degrade: Quarterly Device Health Check.

Backups still matter (UPS ≠ backup)

A UPS buys you time. It doesn’t replace backups. We can set up full-image or cloud backups and test a restore with you.
→ Cloud backup setup

FAQs

How big should my UPS be for a gaming PC?
Add up your worst-case load (PC + monitor). Many gaming rigs sit well above 300 W under load—look at 1500 VA / ~900 W class for 10–20 minutes.

My laptop lasts hours—do I still need a UPS?
You might only need to power the router/ONT so your connection stays up. A small 650 VA works well for that.

Will a UPS fix tripping breakers?
No—solve the underlying electrical issue. A UPS smooths short dips/spikes and keeps devices up briefly.

How long do UPS batteries last?
Typically 2–4 years. Heat and deep discharges shorten life. We can swap batteries and test your unit during a Device Health Check.

Can you help me choose?
Yes—send your device list (Watts if you can) and we’ll recommend a size and brand. Start a Remote support session or ask via Contact us.

Load-shedding survival for laptops/PCs in Stellenbosch: how to size a UPS (with ZAR examples)