At a Glance. The Eaton 5P and the Eaton 9PX are both enterprise-class UPS systems with true sine-wave output — but their topologies target different loads. The 5P is a line-interactive UPS (up to 97 % efficiency) that conditions utility power and switches to battery only on disturbance — ideal for network closets, server rooms and edge IT. The 9PX is an online double-conversion UPS that regenerates clean power continuously (91.5 % efficiency, output power factor 1.0) — the choice for medical, industrial automation and harsh electrical environments. The rule: stable utility, distributed IT, budget-sensitive → 5P; mission-critical, dirty or fluctuating power → 9PX.
1. Head-to-Head Specification Table (representative models)
| Specification | 5P1000 (line-interactive) | 9PX1000IRT2U (online) |
|---|---|---|
| Topology | Line-interactive | Online / double-conversion |
| Rating | 1000 VA / 770 W | 1000 VA / 1000 W |
| Output power factor | 0.77 | 1.0 |
| Efficiency (max load) | 97 % | 91.5 % |
| Output waveform | True sine wave | Sine wave |
| Form factor | Tower | Rack/tower, 2U |
| Dimensions / weight | 9.1×5.9×13.6 in, 25.3 lb | 8.65×44×45 cm, 19.5 kg |
| Operating temperature | 0…35 °C | 0…40 °C |
| Noise | <45 dB at 1 m | <35 dB at 1 m |
| Battery | Sealed lead-acid, user-replaceable | Sealed lead-acid, hot-swappable + EBMs |
| Battery management | ABM 3-stage charging | ABM + temperature-compensated |
| Certifications | cULus Listed | ENERGY STAR certified |
| Stock pages | 5P1000 / 5P1500 | 9PX1000IRT2U / 9PX3000RT |
2. The Deciding Factor: How Clean Does the Power Need to Be?
A line-interactive 5P passes utility power through with voltage correction, switching to battery only on outage — which is why it reaches 97 % efficiency and runs quieter and cooler. The trade-off is a brief transfer time and less complete filtering of sags, swells and frequency drift. For a network closet or edge server on a stable grid, that is an excellent, cost-effective fit.
The online 9PX never passes utility power through at all: it rectifies AC to DC and inverts it back to a clean sine wave continuously, so the load sees perfectly conditioned power with zero transfer time. That is the reason it is specified for medical equipment, industrial automation and sites with generators or poor supply quality — and why it trades some efficiency (91.5 %) for that protection.
3. Secondary Selection Criteria
- Runtime scaling: the 9PX accepts hot-swappable external battery modules (EBMs) for long backup, and the 5P also offers extended-battery variants — size runtime against the load, not just the VA rating.
- Voltage selection: the 5P1000 shown is a 120 V tower (5-15P input); the 9PX shown is a 230 V rack/tower. Match the unit to the site voltage — both families are available across regions.
- Density: the 9PX 2U rack form suits cabinets; the 5P tower (and its wall/rack variants) suits small closets. For higher loads the 9PX scales to 3000 VA and 6–8 kVA models.
- Management: both pair with the Eaton Gigabit network card and IPM/IPP software for monitoring and graceful shutdown — a key differentiator for remote sites.
4. Selection Summary
| Your situation | Recommended UPS |
|---|---|
| Network closet, server room, edge IT on stable grid | 5P |
| Mission-critical / medical / industrial automation | 9PX |
| Dirty or fluctuating power, generator backup | 9PX (online) |
| Long runtime requirement | 9PX + EBMs |
| Budget-sensitive, small load, quiet operation | 5P |
5. Replacement and Cross-Reference
Typical replacement patterns:
- Legacy line-interactive UPS: the 5P family is the direct upgrade — match VA/wattage, input/output receptacles and tower vs rack form.
- Legacy online UPS (double-conversion): the 9PX replaces it with a higher-efficiency, ENERGY STAR online unit — confirm output power factor (the 9PX delivers 1.0, so wattage equals VA) and runtime needs.
Send Glorient the existing UPS model, the connected load in watts and the required runtime, and we will size and quote the correct in-stock Eaton UPS within one business day.
6. FAQ
Why does the 9PX show lower efficiency than the 5P?
Double conversion runs the inverter continuously, which costs a few efficiency points (91.5 % vs 97 %) but buys zero transfer time and continuous power conditioning. For critical loads the protection is worth the extra watts.
What does output power factor 1.0 mean on the 9PX?
It delivers as many watts as VA (1000 VA = 1000 W), so more real power for modern high-PF IT loads. The 5P1000 is 0.77 (1000 VA = 770 W) — size the load in watts, not VA.
Can I add runtime to the 5P?
Yes — the 5P supports extended battery options and the 9PX adds hot-swappable external battery modules. Confirm the correct EBM model and quantity for your target runtime before ordering.
Need a quote? Browse in-stock Eaton UPS solutions — 5P line-interactive and 9PX online UPS — or send your load schedule for a same-week quotation.