100 kW UPS buying guide: compare capacity, batteries and installed scope

Start with the load you actually need to protect

Before requesting a 100 kW quotation, write down what the number means. Is it a measured peak, a planned IT load, a desired frame size, or an allowance for growth? These are different purchasing requirements. Label each figure with its source and date so vendors do not silently interpret an estimate as a measurement.

Eaton separates capacity from runtime in its sizing guidance and asks buyers to consider growth and redundancy. For this purchase, create a load schedule with current, committed and speculative additions in separate columns. Ask the project engineer to determine the design requirement; do not turn a generic percentage allowance into an approved equipment size.

• Identify protected equipment and the boundary of the UPS-backed distribution.
• Record measured kW and kVA, with the measurement period and unusual operating conditions.
• List future additions with an expected date and an owner who can confirm them.
• State the required service outcome during utility failure, maintenance and equipment failure.

Sources: Eaton UPS sizing guide ↗

Compare both kW and kVA, then check the electrical system

Active power and apparent power impose separate constraints. In a hypothetical example, a load of 90 kW at a total power factor of 0.90 corresponds to 100 kVA. That arithmetic describes the load; it does not establish that a particular 100 kW UPS is correctly sized. Transient behavior, redundancy and the installation still need review.

Voltage is not a small-print preference. As one manufacturer example, Schneider Electric publishes a dedicated Galaxy VS specification table for 480 V systems with separate input, output and bypass information. Request the matching technical document for every quoted configuration, including any proposed transformer or switchgear. A voltage entry on a comparison card is insufficient installation documentation.

Sources: Schneider Electric Galaxy VS: Specifications for 480 V systems ↗ · Eaton: VA versus watts and power factor ↗

• Use the kW and kVA explainer ↗

Understand what the 100 kW catalog filter actually means

Power Field Guide normalizes active and apparent output from the ENERGY STAR minimum tested configuration. A family that can be configured at 100 kW may appear under a different value when its minimum tested configuration is smaller. Model-name digits are not a substitute for the source rating.

At the September 12, 2026 catalog snapshot, the exact 100 kW filter returns one source record: EATON S3M100K, ID 4577047, with 100 kW active and 100 kVA apparent output. This is a description of the imported dataset, not a statement that only one 100 kW product exists. Certification data also does not establish stock, current commercial status or installed price.

Sources: ENERGY STAR Certified Uninterruptible Power Supplies dataset ↗ · ENERGY STAR AC UPS certification reporting fields ↗

• See records with 100 kW minimum tested output ↗
• Read the source-backed product record ↗

Make suppliers answer the same purchasing questions

Send a short comparison sheet before accepting a proposal. Keep a column for unanswered items rather than treating silence as inclusion. If one vendor includes batteries and commissioning while another quotes only the power cabinet, the totals cannot yet be compared.

Use the table below as a request for evidence. It is an editorial procurement template, not a specification for any named UPS. Ask the person responsible for the design to approve the technical acceptance criteria before orders are placed.

Treat runtime and operating cost as separate comparisons

Do not accept a battery count as a runtime commitment. Request a manufacturer runtime curve or written sizing output for the exact battery arrangement at the agreed load. Put the promised runtime and the conditions behind it in the same row of your comparison. The runtime guide explains how to review that evidence.

For operating costs, compare the same mode and expected load rather than choosing the highest advertised percentage. ENERGY STAR publishes load-specific efficiency criteria; a certification average is not your utility bill. Request the data needed to build a site-specific loss estimate, then compare service scope, replacement assumptions and the installed quotation separately.

Sources: ENERGY STAR UPS key product criteria ↗

• Review runtime evidence ↗
• Estimate UPS energy losses ↗

Finish with a decision record you can defend

For each shortlisted system, record the evidence received, unresolved questions, responsible reviewer and the next decision. A proposal becomes easier to evaluate when a missing battery document has a named owner instead of disappearing into an email chain.

Before award, ask the selected supplier to reconcile its final bill of materials with the reviewed proposal. Keep the approved configuration and commissioning requirements with the purchase record. If a substitution appears later, route it back through the same review instead of relying on a similar-looking model name.

Common questions