Code Reference
EnergyASHRAE 90.1-2022

Section 6.4.1/HVAC Equipment Efficiency

ASHRAE 90.1 Section 6.4.1 establishes minimum efficiency ratings for HVAC equipment including chillers, boilers, and heat pumps.

What this section requires

All HVAC equipment must meet or exceed the minimum efficiency ratings in the applicable efficiency table at the time of installation. For unitary air conditioners and heat pumps, efficiency is specified as SEER2 or EER2. For chillers, efficiency is specified as full-load kW/ton and IPLV. For boilers, efficiency is specified as thermal efficiency or combustion efficiency. Equipment must be listed by an approved agency and rated under the applicable AHRI or ASHRAE test standard.

Why this section exists

HVAC equipment efficiency has the largest single impact on building energy consumption. A chiller that operates at 0.55 kW/ton uses 10% less energy than one at 0.61 kW/ton over its lifetime. The minimum efficiency requirements ensure that all new equipment meets a reasonable performance baseline, preventing the installation of low-cost, low-efficiency equipment that wastes energy for 15-25 years.

What plan reviewers look for

Plan reviewers check the mechanical equipment schedule for efficiency ratings and compare them against the applicable table in Section 6.8.1. They verify the equipment type, capacity range, and heating type match the correct table row. They check that the rating metric (SEER2 vs. EER2 vs. IEER) matches what the table requires for that equipment type and capacity.

Common violations

Equipment efficiency below table minimum
The equipment schedule shows an efficiency rating below the minimum from the applicable Table 6.8.1 for the equipment type and capacity. This can occur when equipment is selected on first cost.
Wrong efficiency metric used
The schedule reports SEER when the table requires SEER2, or reports EER when IEER is required. The 2022 edition of ASHRAE 90.1 uses the updated SEER2/EER2/HSPF2 metrics that differ from previous editions.
Efficiency not shown on equipment schedule
The mechanical equipment schedule lists capacity and model numbers but omits the efficiency rating. The reviewer cannot verify compliance without the efficiency value on the drawings.
Compliance tip
Include the efficiency rating on the mechanical equipment schedule for every piece of HVAC equipment. Note the rating metric (SEER2, EER2, kW/ton, IPLV, thermal efficiency) and reference the applicable ASHRAE 90.1 table. Verify the correct metric for the equipment type and capacity range.

Related ASHRAE 90.1 requirements

Section 6.5 covers HVAC system controls including economizers and demand control ventilation. Section 6.4.3 covers duct and piping insulation. IECC Section C403.3 provides equivalent equipment efficiency requirements. Section 6.5.1 covers economizer requirements.

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Related sections

C403.1Mechanical Systems ScopeIECC 20215.5.3Opaque Envelope Insulation RequirementsASHRAE 90.1-20225.5.4Fenestration RequirementsASHRAE 90.1-2022