ANSI/RESNET/ICC 380-2025 Standard for Testing Airtightness of Building, Dwelling Unit, and Sleeping Unit Enclosures; Airtightness of Heating and Cooling Air Distribution Systems; and Airflow of Mechanical Ventilation Systems

This standard establishes a consistent, uniform methodology for evaluating the airtightness of dwelling and sleeping unit enclosures, the airtightness of heating and cooling air distribution systems, and the airflows of mechanical ventilation systems. Designed for use by energy raters, auditors, code officials and HVAC professionals, it provides test procedures that support building diagnostics, quality assurance, code compliance and accurate inputs for energy simulation models.

Recognizing that dwelling units and HVAC system characteristics vary widely and that different codes and standards prescribe their own requirements, this standard presents multiple approved test options for each measurement. These alternative pathways provide the flexibility needed to apply the standard effectively across a range of building types and conditions.

The 2025 edition expands on prior versions to further support consistent testing procedures for dwelling and sleeping units in buildings of any height, reflecting advancements in field practices, testing technologies and industry expectations.

This book includes:

• Uniform procedures for testing the airtightness of dwelling and sleeping unit enclosures
• Methods for evaluating airtightness of heating and cooling air distribution systems
• Approved procedures for measuring airflow of mechanical ventilation systems
• Applications for building diagnostics, QA/QC programs, code compliance and energy modeling
• Multiple alternative test approaches to accommodate varying building types and system configurations