Duct Leakage Testing
Find out how much conditioned air your duct system is wasting — and get the certified report your building department requires.
What Is Duct Leakage Testing?
Your duct system is supposed to deliver conditioned air from your furnace or air handler directly to your living spaces. But in most homes, a significant portion of that air never arrives — it leaks out through gaps, loose connections, and unsealed joints into attics, crawlspaces, and wall cavities.
A duct leakage test (also called a duct blaster test) pressurizes your duct system and measures exactly how much air escapes before reaching your rooms. The result is expressed as CFM25 — cubic feet per minute of leakage at 25 Pascals of pressure.
This test is required for new construction under IECC 2021 in most Midwest states, and it's one of the most impactful diagnostics you can run on an existing home with high energy bills or comfort problems.
How the Test Works
Setup
We connect our calibrated duct blaster fan to the air handler or a supply register. All supply and return registers are temporarily sealed with covers. Setup takes about 20 minutes.
Pressurization
We pressurize the duct system to 25 Pascals and measure the airflow required to maintain that pressure. The more leaky the ducts, the harder the fan has to work.
Total vs. Outside Leakage
We can test total duct leakage (all leaks) or leakage to outside only (leaks into unconditioned spaces like attics). For code compliance, leakage to outside is the key metric.
Report & Documentation
You receive a certified report with your CFM25 result, pass/fail status against IECC 2021 thresholds, and documentation formatted for building department submittal.
Code Compliance & Standards
What the rules require — and what we deliver.
≤ 4 CFM25 per 100 sq ft of conditioned floor area (total leakage) or ≤ 3 CFM25 per 100 sq ft (leakage to outside)
Adopted in most Midwest states for new construction. Our reports are formatted to satisfy building department requirements.
≤ 4 CFM25 per 100 sq ft total duct leakage
Required for Energy Star certified new homes. We provide the documentation needed for certification.
No code requirement, but testing reveals improvement opportunities
Even without a code mandate, duct testing is one of the highest-ROI diagnostics for existing homes with comfort or efficiency problems.
Why Test Your Ducts?
For Homeowners
- Diagnose rooms that never get warm or cool enough
- Find the source of high heating and cooling bills
- Identify duct leaks before sealing work begins — and verify results after
- Qualify for utility rebates that require a certified duct test
- Improve indoor air quality by reducing duct infiltration from attics and crawlspaces
For Contractors & Builders
- Meet IECC 2021 duct leakage requirements for new construction
- Certified third-party test report accepted by building departments
- Fast scheduling — we work around your construction timeline
- Combined blower door + duct testing available for full code compliance in one visit
Need a duct test for your project?
We provide fast, certified duct leakage testing for new construction and existing homes across the Midwest.