Ductwork Hub — Testing
Duct Leakage Testing in Texas Homes
Written and technically reviewed by Sergio Villarreal, Texas Licensed HVAC Contractor — TACLB50985E.
Duct leakage testing is how you measure — not guess — where your conditioned air is going. In DFW attics, 20–40% of system airflow is commonly lost before it ever reaches a room. Without testing, that loss is invisible.
Testing is the foundation of real ductwork airflow problem diagnosis. Sealing without it is just hoping.
What the Test Actually Measures
- Total leakage: CFM lost from the entire duct system at a calibrated test pressure.
- Leakage to outside: the air leaving the conditioned envelope entirely — the costliest kind.
- Leakage location: identified by attic inspection, smoke testing, and pressure mapping.
Where Air Is Lost in DFW Attics
- Air handler cabinet seams (often the single largest leak).
- Plenum-to-trunk connections.
- Boot-to-drywall connections at every register.
- Failed mastic, dried tape, and pulled-loose flex collars.
- Return-side leaks pulling 130°F+ attic air directly into the system.
Why Testing Has to Come First
Sealing without testing is how homeowners pay for work that doesn't move the needle. We test before, target the actual leak sources during sealing, and re-test after to verify the improvement.
That before/after measurement is the difference between a sealing job and a sealing claim.
Common Questions
Q: How long does a leakage test take?
Q: Is leakage testing the same as a blower door test?
← Back to the DFW Ductwork & Airflow Hub for the full diagnostic framework.
Get the real diagnosis before you replace anything.
Technical Sources
- Air Conditioning Contractors of America (ACCA) — Residential Technical Toolbox (Manual J, D and S guidance)
- ENERGY STAR — HVAC Quality Installation
- U.S. Environmental Protection Agency — What can I do to improve the indoor air quality in my home?
These references provide general industry, regulatory and public-health guidance. Their inclusion does not imply endorsement of Too Cool Air.