Blower Door Testing Explained
Blower door testing is a diagnostic method used to measure a building’s airtightness. It helps identify air leakage pathways that affect energy performance, comfort, and moisture control, making it a crucial step in modern building science.
What Is Blower Door Testing?
A blower door is a powerful fan mounted into an exterior doorway. When activated, it depressurizes the building, causing outside air to enter through unsealed gaps.
This test allows us to:
- Measure total air leakage (in CFM)
- Locate cracks, gaps, or poorly sealed penetrations
- Identify energy loss zones and comfort issues
It’s a key tool for both new construction and existing buildings undergoing performance upgrades.
Why Airtightness Matters
- Energy Efficiency
Uncontrolled air exchange increases heating and cooling loads, raising energy bills. - Moisture Control
Leaky envelopes allow humid air in, risking condensation and mold growth. - Comfort & Air Quality
Drafts, inconsistent temperatures, and pollutant infiltration all stem from excessive leakage. - Code Compliance & Certification
Blower door results are often required for energy codes, green building standards, and performance verification.
How RAC Conducts Blower Door Testing
Our trained consultants use calibrated equipment to run the test and interpret results in real-time. We provide:
- Quantitative leakage data (ACH, CFM)
- Smoke testing or infrared pairing to visualize leaks
- Airtightness improvement strategies
- Before/after testing to validate air sealing work
When Should You Get a Blower Door Test?
- During building envelope commissioning
- Before and after major renovations or insulation upgrades
- When investigating high utility bills or IAQ concerns
- For LEED, ENERGY STAR®, or HERS rating requirements
Need a precise airtightness assessment? Schedule a blower door test with RAC and take control of your building’s performance.