DOE Adopts ASHRAE 90.1-2025: Cooling Tower Efficiency Up 18%

On May 5, 2026, the U.S. Department of Energy (DOE) formally adopted the ASHRAE 90.1-2025 standard, raising minimum efficiency requirements for commercial cooling towers by 18%—a shift directly affecting U.S.-bound exports, federal procurement eligibility, and large-scale commercial HVAC projects.

Event Overview

The U.S. Department of Energy adopted ASHRAE Standard 90.1-2025 on May 5, 2026. Under this update, all open- and closed-circuit cooling towers imported into the United States must meet a new mandatory minimum Integrated Energy Efficiency Ratio (IEER) of ≥5.8—up 18% from the IEER threshold in the 2019 edition. The requirement takes effect on October 1, 2026. Compliance requires third-party certification to AHRI Standard 204, administered by an AHRI-accredited laboratory.

Industries Affected

Direct Exporters (U.S.-Bound Cooling Tower Manufacturers)

Manufacturers exporting cooling towers to the U.S. market—including those based in China—are directly subject to the new IEER mandate. Non-compliant units will be barred from entry at U.S. customs and excluded from federal government procurement and major commercial tenders.

Component & Subsystem Suppliers

Suppliers of fan motors, variable frequency drives (VFDs), heat transfer fill materials, and control systems may face revised specification demands. Higher IEER compliance often requires upgrades to motor efficiency (e.g., IE4-class), precision airflow control, or enhanced thermal performance of fill media—potentially triggering design and sourcing adjustments.

Testing & Certification Service Providers

Third-party laboratories and certification bodies accredited under AHRI Standard 204 will see increased demand for IEER testing and verification. Firms without current AHRI accreditation—or lacking capacity for post-2025 test protocols—may lose access to U.S.-focused clients.

Distribution & Project Integration Channels

U.S. distributors, engineering contractors, and EPC firms specifying cooling towers for data centers, hospitals, or district energy systems must now verify AHRI 204 certification prior to bid submission or equipment ordering. Inventory planning, lead-time forecasting, and technical documentation review will require tighter alignment with DOE compliance timelines.

What Stakeholders Should Monitor and Do Now

Confirm AHRI 204 Certification Readiness

Exporters and manufacturers should verify whether their current product lines have undergone—and passed—AHRI Standard 204 testing for IEER ≥5.8. Units certified under earlier versions (e.g., AHRI 204–2015) do not satisfy the updated requirement. Re-testing is mandatory if certification predates the 2025 protocol revision.

Review Product Documentation and Labeling

From October 1, 2026, all cooling tower units shipped to the U.S. must bear AHRI-certified IEER values on nameplates and submittal documents. Mislabeling or omission risks rejection during federal contract review or state-level code enforcement inspections.

Assess Supply Chain Lead Times for Compliance-Critical Components

Upgrades to meet IEER ≥5.8 may require higher-efficiency motors, optimized fan blades, or recalibrated control logic. Procurement teams should map lead times for these components—especially if sourced from suppliers with limited AHRI-aligned validation experience—to avoid delays ahead of the October 2026 deadline.

Track State-Level Adoption Timing

While DOE’s adoption triggers federal procurement rules, individual U.S. states adopt ASHRAE 90.1 into local building codes at varying paces. Some states may delay implementation beyond October 2026; others may enforce it earlier. Monitoring state-specific code adoption schedules helps prioritize regional sales and compliance efforts.

Editorial Perspective / Industry Observation

Observably, this update functions less as an isolated regulatory change and more as a calibrated signal of tightening federal energy policy toward HVAC infrastructure—particularly for high-energy-use systems in commercial buildings. Analysis shows that the 18% IEER increase aligns with broader DOE goals under the Building Energy Codes Program, aiming for cumulative national energy savings of ~3.5 quads by 2040. From an industry perspective, the timeline (May 2026 adoption, October 2026 enforcement) leaves narrow margin for retrofitting legacy designs—making pre-certification and early lab engagement critical. It is better understood not as a one-time compliance hurdle, but as the first step in a multi-cycle tightening trajectory, where future ASHRAE updates are likely to further raise IEER floors or introduce additional metrics (e.g., part-load performance weighting).

Conclusion: The DOE’s adoption of ASHRAE 90.1-2025 marks a definitive escalation in minimum efficiency expectations for commercial cooling towers entering the U.S. market. Its significance lies not only in the 18% IEER uplift itself, but in its binding effect on procurement eligibility and supply chain readiness. At present, it is most accurately interpreted as an enforceable operational requirement—not merely a policy signal—with tangible consequences for export strategy, product development cycles, and technical certification workflows.

Source: U.S. Department of Energy (DOE) Federal Register Notice, Docket No. EERE-2023-BT-STD-0072; ASHRAE Standard 90.1-2025 official publication; AHRI Standard 204–2025 edition. Note: State-level adoption timelines remain subject to ongoing review and vary by jurisdiction.