E91 10 kVA vs Liebert EXS10KN
The Xtreme Power E91 10 kVA and the Liebert EXS10KN are online double-conversion UPS systems for 208/120V three-phase applications, both delivering full 10 kVA / 10 kW with internal VRLA batteries. The E91 delivers significantly longer internal runtime, a dramatically smaller cabinet, and broader standard warranty and start-up coverage; the EXS10KN offers comparable efficiency and battery chemistry in a substantially larger enclosure.
Where the E91 10 kVA leads
- Significantly longer internal runtime (11 vs 6 min @ 10 kW).
- A dramatically smaller cabinet footprint (9.9 × 26.3 × 32.3 in vs 13 × 25.6 × 51.2 in).
- Full 10 kVA / 10 kW usable output.
- Equivalent high-efficiency operation.
- Broader standard warranty with start-up included.
10 kVA three-phase UPS, side by side
| Specification | Xtreme Power E91 10 kVA | Vertiv Liebert EXS10KN | Advantage |
|---|---|---|---|
| Rated capacity | 10 kVA / 10 kW | 10 kVA / 10 kW | Equal usable power |
| Voltage | 208/120V, 3-phase | 208/120V, 3-phase | Direct electrical match |
| UPS topology | Online double-conversion | Online double-conversion | Equivalent protection |
| Battery architecture | Internal VRLA batteries | Internal VRLA batteries | Equivalent chemistry |
| Internal runtime (full load) | 11 min @ 10 kW | 6 min @ 10 kW | Longer standard runtime |
| Efficiency (online / ECO) | Up to 94% / 98% | Up to 94% / 99% | Comparable; EXS 99% ECO |
| Dimensions (W × D × H) | 9.9 × 26.3 × 32.3 in | 13 × 25.6 × 51.2 in | Much smaller footprint |
| Output distribution | Optional receptacles | Optional receptacles | Equivalent flexibility |
| Warranty & start-up | 2-year + start-up included | 1-year standard | Broader coverage |
| TAA compliance | TAA compliant | TAA available | Eligible for federal procurement |
Both are true online double-conversion three-phase UPS with full 10 kW usable output and internal VRLA batteries. The E91 leads on internal runtime (11 vs 6 min), a much smaller cabinet, and broader warranty with start-up included; the EXS posts a marginally higher ECO figure (99 vs 98%). Confirm Liebert EXS specifications against current Vertiv documentation.
Choosing between them
With equal usable capacity and comparable efficiency, the decision turns on runtime, footprint, and coverage. Choose the E91 for longer full-load runtime, a dramatically smaller cabinet, and broader warranty with start-up; the EXS10KN fits where an existing Vertiv standard governs.
Choose the E91 10 kVA if you need
- Longer runtime at full rated load
- A dramatically smaller UPS footprint
- Full 10 kW usable capacity
- Integrated start-up coverage
- Longer standard warranty
The Liebert EXS10KN may fit if you need
- Facilities standardized on Vertiv infrastructure
- Alignment with existing EXS deployments
- Vertiv service ecosystem continuity
Related comparisons
Standardizing compact three-phase UPS across your facilities?
Xtreme Power supports E91 three-phase UPS sizing, runtime planning with external battery cabinets, modernization strategy for legacy three-phase UPS, and TAA-compliant procurement for healthcare, education, retail, industrial, and enterprise infrastructure.