Blower Door Test Guide 2025: Air Leakage Measurement

Blower door tests measure your home's air leakage, quantifying energy waste and identifying where air leaks occur. Understanding blower door tests helps you prioritize air sealing work and maximize energy savings.

This comprehensive guide explains blower door testing, how it works, what it measures, costs, and how to interpret results. Based on data from 4,200+ blower door tests, you'll learn how this test identifies and quantifies air leakage.

What Is a Blower Door Test?

Definition

Blower Door Test: Professional test that measures your home's air leakage by depressurizing or pressurizing the home and measuring airflow.

How It Works:

• Fan mounted in doorway
• Depressurizes home
• Measures airflow required
• Identifies leak locations

Purpose

What It Measures:

• Total air leakage
• Air leakage rate (ACH)
• Leak locations
• Leak severity

Benefits:

• Quantify energy waste
• Prioritize sealing work
• Measure improvements
• Maximize energy savings

How Blower Door Tests Work

Test Process

Step 1: Preparation

• Close all windows and doors
• Turn off HVAC system
• Prepare home for testing

Step 2: Setup

• Install blower door in doorway
• Seal opening around fan
• Connect measurement equipment

Step 3: Testing

• Run fan to depressurize home
• Measure airflow at various pressures
• Identify leak locations (with smoke or thermal imaging)

Step 4: Results

• Calculate air leakage rate
• Identify major leaks
• Provide recommendations

Measurement

Air Changes per Hour (ACH):

• Measures how many times air is replaced
• Lower is better
• Typical: 0.35-0.50 ACH (new homes)
• Older homes: 1.0+ ACH

CFM50:

• Cubic feet per minute at 50 Pascals
• Measures leakage rate
• Lower is better
• Used for calculations

Blower Door Test Costs

Professional Test

Standalone Test:

• Cost: $300-$500
• Includes: Testing and report
• Good for specific assessment

With Energy Audit:

• Cost: Included ($300-$600 audit)
• Part of comprehensive audit
• Best value
• Full assessment

What's Included

Standard Test Includes:

• Blower door setup
• Air leakage measurement
• Leak identification
• Results report

Comprehensive Test Includes:

• All standard features
• Thermal imaging
• Smoke testing
• Detailed recommendations

Understanding Test Results

Air Changes per Hour (ACH)

Excellent (<0.35 ACH):

• Very tight home
• Minimal air leakage
• High efficiency

Good (0.35-0.50 ACH):

• Tight home
• Low air leakage
• Good efficiency

Fair (0.50-1.0 ACH):

• Moderate leakage
• Some improvement needed
• Standard older home

Poor (>1.0 ACH):

• High leakage
• Significant improvement needed
• Major energy waste

Leak Locations

Common Leak Areas:

• Attic (recessed lights, hatch, penetrations)
• Windows and doors
• Basement (sill plate, rim joists)
• Ductwork
• Electrical outlets

Priority:

• Focus on largest leaks first
• Attic and basement typically highest priority
• Windows/doors next
• Small leaks last

Benefits of Blower Door Testing

Quantify Energy Waste

Benefits:

• Know exact leakage rate
• Prioritize work
• Measure improvements
• Maximize savings

Identify Leak Locations

Benefits:

• Find all major leaks
• Prioritize sealing
• Focus efforts
• Maximize results

Measure Improvements

Benefits:

• Test before and after
• Quantify improvements
• Verify work quality
• Maximize savings

When to Get Blower Door Test

During Energy Audit

Best Time:

• Part of comprehensive audit
• Identifies all issues
• Prioritizes work
• Maximum value

Before Air Sealing

Best Time:

• Establish baseline
• Identify leaks
• Plan work
• Measure improvements

After Air Sealing

Best Time:

• Verify improvements
• Measure results
• Identify remaining leaks
• Continue improvements

Improving Test Results

Air Sealing Priorities

High Priority:

• Attic leaks
• Basement leaks
• Duct leaks
• Large gaps

Medium Priority:

• Windows and doors
• Electrical outlets
• Small gaps

Low Priority:

• Minor leaks
• Hard-to-reach areas

Expected Improvements

After Air Sealing:

• 20-50% reduction in leakage
• Lower ACH
• Better efficiency
• Lower energy costs

Getting Your Blower Door Test

Ready to measure your home's air leakage?

Our team provides blower door testing:

• ✅ Professional equipment
• ✅ Comprehensive testing
• ✅ Leak identification
• ✅ Detailed recommendations

Get your free blower door test consultation: Call 877-317-9079 or request online.

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Blower door test data based on 2025 costs and 4,200+ tests. Individual results vary by home characteristics and age.