EER to kW/Ton Calculator

US manufacturers typically rate equipment in EER, while European and Asian bidders use kW/ton or COP.

ASHRAE 90.1 sets minimum EER requirements by equipment type and capacity.

For energy modeling and life-cycle cost analysis, convert everything to kW/ton for a common efficiency baseline.

Also useful for verifying utility rebate eligibility, which often requires minimum EER thresholds.

In chiller bid evaluation and selection, the EER-to-kW/ton conversion is the primary tool for comparing equipment from different manufacturers using different rating systems — a US bid showing EER 10.5 for a 200-ton water-cooled centrifugal chiller and a German bid showing 1.14 kW/ton (or COP 3.08) for an equivalent Trane/Carrier/DAIKIN model represent the same efficiency (1.14 kW/ton = 12/10.5 = 1.143 kW/ton from the US bid, a 0.3% difference well within test tolerance).

The conversion allows the engineer to make a fair comparison and proceed to other selection criteria (capacity turndown, sound, service, parts availability, warranty).

ASHRAE 90.1-2019 Table 6.8.1-3 (and the more recent 90.1-2022 and 90.1-2025) specifies the minimum EER and IPLV for chillers by equipment type and capacity, with air-cooled chillers below 150 tons requiring EER ≥ 10.0 (1.20 kW/ton), water-cooled centrifugal chillers below 300 tons requiring EER ≥ 15.9 (0.755 kW/ton), and the requirements increasing with capacity.

Building energy modeling and life-cycle cost analysis (LCCA) per ASHRAE 90.1 Appendix F uses kW/ton as the input to the energy cost calculation, with the chiller efficiency directly determining the annual energy cost and the 20- or 30-year present value.

Utility rebate programs for high-efficiency chillers (Focus on Energy, Mass Save, NYSERDA, ENERGY STAR for chillers) typically require a minimum efficiency above the ASHRAE 90.1 baseline by 5–15%, with the rebate amount proportional to the kW/ton reduction.

The conversion from EER to kW/ton is used at the rebate application step to verify eligibility.

LEED v4.1 and the newer LEED v5 for Building Design and Construction have minimum efficiency requirements (EER or COP) for the HVAC equipment, and the conversion to kW/ton is used in the energy modeling documentation for the LEED submission.

The US DOE Building Energy Codes Program and the ENERGY STAR Most Efficient recognition for chillers use kW/ton as the primary comparison metric.

Data center chiller selection per ASHRAE TC 9.9 and the 2024 ASHRAE Liquid Cooling Guidelines specifies high-efficiency chillers (typically water-cooled centrifugal or screw at 0.50–0.65 kW/ton) for the high-density IT load, with the conversion applied at the equipment specification step.