Blower door testing is one of the most effective ways to measure airtightness and verify building envelope performance. In Oregon, both residential and commercial buildings are required to meet specific air leakage limits under the International Energy Conservation Code (IECC) and related ASTM standards. While the objective is the same—reducing uncontrolled air leakage—the testing methods, equipment, metrics, and performance targets differ significantly between residential and commercial projects.
This article explains the key differences between residential blower door testing in Oregon and commercial blower door testing in Oregon, why each is important, and which standards govern the testing process.
What Is Blower Door Testing?
Blower door testing is a diagnostic procedure used to measure how much air leaks through a building’s envelope. A calibrated fan is temporarily installed in an exterior doorway or opening to pressurize or depressurize the structure. By measuring airflow and pressure differences, testers can calculate the building’s overall air leakage rate and identify areas where air escapes.
In Oregon, blower door testing is a required component of energy code compliance for new construction and major renovations. The results help ensure buildings meet airtightness requirements, improve energy efficiency, and reduce long-term operating costs.
Residential Blower Door Testing in Oregon
Residential blower door testing applies to single-family homes and smaller residential buildings. Testing is typically conducted in accordance with ASTM E779 or ASTM E1827.
- ASTM E779 outlines the standard fan pressurization method used to determine air leakage rates. Results are expressed as air changes per hour at 50 Pascals (ACH50), indicating how many times the home’s air volume is replaced each hour under test conditions.
- ASTM E1827 provides an alternative testing method that may be used for smaller or simpler structures, offering flexibility while maintaining accuracy.
Under the Oregon Residential Specialty Code (ORSC), most new homes are required to achieve 3 ACH50 or less, depending on climate zone.
Residential blower door testing typically uses a single fan system, as the air volume of a home can be accurately measured with smaller equipment. Test results help identify common leakage locations such as windows, doors, attics, rim joists, and plumbing or electrical penetrations—allowing builders to make corrections that improve comfort, reduce drafts, and lower energy bills.
Commercial Blower Door Testing in Oregon
Commercial, multifamily, and large mixed-use buildings require more advanced testing procedures due to their size, height, and complex mechanical systems. These projects are commonly tested under ASTM E3158, the standard specifically developed for large or multizone buildings.
Key differences in commercial blower door testing include:
- Multiple high-capacity fans are used to move enough air to pressurize large buildings.
- Testing is performed at 75 Pascals, rather than 50 Pascals.
- Results are reported in cubic feet per minute per square foot (CFM/ft²) of building envelope area, rather than ACH.
The Oregon Energy Efficiency Specialty Code (OEESC) references IECC Section C402.5, which sets the maximum allowable air leakage rate for most new commercial buildings at 0.40 CFM/ft² at 75 Pa. This performance-based metric allows accurate comparison across large buildings of varying sizes and configurations.
Key Differences at a Glance
|
Feature |
Residential Testing |
Commercial Testing |
|
Governing Standards |
ASTM E779, ASTM E1827 |
ASTM E3158 |
|
Test Pressure |
50 Pascals |
75 Pascals |
|
Leakage Metric |
ACH50 |
CFM/ft² |
|
Equipment |
Single fan |
Multiple high-capacity fans |
|
Code Reference |
ORSC |
OEESC / IECC |
|
Typical Building Size |
Homes, small residential |
Large commercial & multifamily |
Why Blower Door Testing Matters
Uncontrolled air leakage increases heating and cooling costs, reduces comfort, and can introduce moisture into wall and roof assemblies—leading to long-term durability issues. Blower door testing verifies that the building envelope performs as designed and meets Oregon’s energy efficiency requirements.
By following standards such as ASTM E779, ASTM E1827, and ASTM E3158, project teams can:
- Demonstrate energy code compliance
- Improve HVAC efficiency and system performance
- Reduce moisture-related risks
- Enhance occupant comfort and indoor air quality
- Support Oregon’s sustainability and carbon-reduction goals
Professional Blower Door Testing in Oregon
Accurate blower door testing requires trained technicians, calibrated equipment, and a strong understanding of Oregon-specific code requirements. Proper testing provides clear documentation for code officials, commissioning teams, and building owners, helping projects avoid delays and costly corrective work.
Whether for residential or commercial construction, blower door testing is a critical quality-control step that improves energy performance, durability, and long-term building value.
Final Thoughts
Residential and commercial blower door testing serve the same fundamental purpose—measuring and controlling air leakage—but they differ greatly in scale, standards, and evaluation metrics. Residential testing focuses on occupant comfort and ACH-based targets, while commercial testing addresses the complexity and performance demands of large buildings using envelope-area metrics.
Together, these testing methods play a vital role in meeting Oregon’s energy codes and delivering high-performing, efficient buildings across the state.