ANSI/RESNET/ICC/ACCA 310-2025 Standard for Grading the Installation of HVAC Systems

This standard provides a consistent, technically rigorous framework for evaluating and grading the design and installation of residential HVAC systems. Developed to support accuracy in energy rating and labeling programs, it establishes the required procedures, tolerances, and documentation practices used by home energy raters, energy auditors, and HVAC contractors.

Applicable to unitary HVAC systems, the standard outlines a structured, five-task process, each building on the last, to ensure proper system performance. As each task is completed, results are assessed against clearly defined thresholds. Design tolerances govern the first task, while installation quality grades determine compliance for tasks two through five. Completion of each task is required before advancing to the next, reinforcing a disciplined, step-by-step evaluation that promotes consistency and quality across the industry.

This book Includes:

• Required procedures and tolerances for evaluating HVAC design and installation
• Documentation and record-keeping requirements to support accurate energy rating and labeling
• Applicability and scope for unitary residential HVAC systems
• The five sequential evaluation tasks: Task 1: Design review and verification of design tolerances, Task 2: Total duct leakage testing, Task 3: Blower fan volumetric airflow testing, Task 4: Blower fan watt draw testing, Task 5: Noninvasive refrigerant charge evaluation
• Compliance thresholds for each task and their role in determining progression through the evaluation sequence
• Quality grading criteria for installation performance (Tasks 2–5)