Blower door testing is one of the most important steps in ensuring a building meets energy efficiency standards, reduces utility costs, and provides a comfortable indoor environment. While single-point testing offers a quick reading, multi-point blower door testing is now the industry standard for energy code compliance in Washington State and beyond.
This blog explains what multi-point testing is, why it’s required, and how it helps builders, contractors, and homeowners achieve airtight, code-compliant buildings.
A multi-point blower door test uses a calibrated fan and digital manometer to measure air leakage at multiple pressure levels—typically between 10 and 60 Pascals. By taking readings at multiple points, the technician can:
Accurately calculate the building’s air changes per hour at 50 Pascals (ACH50).
Verify compliance with the 2021 Washington State Energy Code blower door requirements.
Provide data for RESNET/ANSI 380 and ASTM E779 standards.
This method produces a more accurate leakage curve compared to a single-point test, ensuring reliable results for both residential and commercial buildings.
Multiple readings reduce error, producing a true picture of building airtightness.
Homes must meet 3.0 ACH50 or less, and commercial buildings must achieve 0.40 cfm/sf @ 75 Pa. Multi-point testing is the most reliable way to prove compliance.
Utility rebates, weatherization programs, and ENERGY STAR certification often require multi-point blower door testing.
The pressure-flow curve helps inspectors pinpoint leakage areas and make recommendations for air sealing.
Preparation – All exterior doors/windows are closed, interior doors open, HVAC off, and combustion appliances checked.
Baseline Pressure – The natural indoor/outdoor pressure is recorded.
Multi-Point Fan Test – The blower door runs at 10–60 Pascals in increments.
Data Logging – Software records air flow at each pressure step.
Results Reported – Metrics such as CFM50, ACH50, and effective leakage area are calculated.
Home Builders – For Washington State Energy Code compliance.
Contractors – To pass inspections and avoid costly delays.
Property Managers – For retrofits, weatherization, and rebate programs.
Commercial Projects – To ensure large buildings meet tight energy performance standards.
Homeowners – To reduce energy bills and improve indoor comfort.
The Pacific Northwest is known for its progressive energy codes. In Washington, Oregon, and surrounding states, failing a blower door test can delay occupancy permits and add unexpected costs. That’s why certified multi-point testing is the safest way to guarantee compliance and keep projects on schedule.
At Pacific Northwest Inspections Group (PNWIG), we specialize in blower door testing for Washington State Energy Code compliance. Our certified team delivers accurate, code-ready reports for single-family homes, multifamily projects, and commercial buildings.
👉 Call us today at 425-608-9553 to schedule your multi-point blower door test and keep your project on track.
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⚡ Pro Tip: Call PNWIG @ 425-608-9553
