← Better-Built Homes series • Article 9 of 9
A home can contain excellent products and still underperform if their connections are incomplete. Performance testing helps turn “energy efficient” from a general description into something you can evaluate. For a custom home, addition, or major remodel, agree on the tests and documentation while the scope is being developed.
What does a blower-door test measure?
A blower door uses a calibrated fan and pressure measurement to evaluate enclosure air leakage. Results may include CFM50—airflow in cubic feet per minute at a 50-pascal test pressure—and ACH50, air changes per hour at that same test pressure. PNNL explains how these measurements relate to house volume.[1]
ACH50 = CFM50 × 60 ÷ tested enclosure volume in cubic feet. If the measured leakage is 1,000 CFM50 and the tested volume is 20,000 cubic feet, the result is 3 ACH50. This is a hypothetical example. It is not a code limit, ADDRAC target, or prediction of ordinary daily ventilation.
Lower leakage under the test conditions means a tighter enclosure. The result does not prove that the house has adequate fresh-air ventilation, acceptable indoor humidity, or no water leaks. Those require separate evaluation. Different test boundaries or methods can also make numbers difficult to compare.
Test while repairs are still accessible
Discuss whether an interim test can help find enclosure gaps before finishes conceal them, followed by any required final test. Air-barrier transitions, service penetrations, attic connections, and access openings are useful places to investigate. Document the boundary being tested and the work needed to meet the agreed criteria.
For an addition, establish whether the test covers the whole connected home or a defined portion and what the jurisdiction or program requires. Do not promise that a limited new scope can make an older house meet a whole-house target without evaluating the existing enclosure.
Duct testing answers a different question
Duct leakage tests evaluate the distribution system rather than the entire building enclosure. PNNL distinguishes total leakage from leakage to outside, which can require a completed enclosure and coordinated test setup.[2] A tight house can still have leaking ducts, and a tight duct system does not establish that every room receives the right airflow.
| Verification | What to request | What it does not establish alone |
|---|---|---|
| Enclosure leakage test | Method, boundary, volume, measured result, and applicable pass criteria. | Ventilation adequacy or water tightness. |
| Duct leakage test | Total versus outside leakage, test pressure, normalization, and result. | Room airflow balance or correct equipment sizing. |
| Ventilation airflow measurement | Actual delivered or exhausted airflow and operating controls. | Removal of every pollutant or year-round humidity control. |
| Insulation / concealed-work inspection | Coverage, fit, product details, and photographs before concealment. | The performance of unrelated enclosure components. |
| HVAC startup and commissioning | Required manufacturer checks, controls, drainage, and documented operating conditions. | A guaranteed energy bill. |
Measure the ventilation you designed
A fan’s label is not a measurement of airflow delivered through the installed duct route. PNNL provides guidance on checking mechanical ventilation airflow.[3] Ask for the measured result, settings, and homeowner instructions. Review outdoor intakes and exhaust terminations before completion.
Have the mechanical designer connect equipment selection and controls to the actual loads and moisture needs. Document filter compatibility, service access, condensate disposal, and room comfort findings. The commissioning scope should identify responsibilities rather than simply rely on “HVAC installed.”
Code compliance and voluntary targets are separate
Confirm the governing code, permit conditions, and testing qualifications for your project. Austin’s technical-code page lists its current adopted editions and local amendments, plus resources for energy-code testing.[4] Other cities may have different requirements. If a voluntary rating or certification is desired, specify its program, verifier, and documentation separately.
There is no single ACH50 target appropriate to every existing-home remodel. An ambitious number belongs in the contract only when the scope, design, ventilation strategy, and verification method support it.
Where to spend your budget
Our suggested approach is to identify measurable priorities early, inspect concealed work, and leave time for correction and retesting. Request a handover package with results, equipment information, filter specifications, warranty documents, and maintenance instructions. Clear documentation helps you understand what was built and supports future service.
Testing is useful because it can identify particular issues. It is not a substitute for structural, electrical, plumbing, moisture, or other required inspections. A better-built home combines design, workmanship, inspections, and measurements rather than relying on one impressive score.
Plan a better-built home with ADDRAC.
Planning a custom home, addition, or major remodel? Contact ADDRAC Construction to discuss the performance goals, inspections, and verification appropriate to your project. Request an estimate that identifies the construction scope and testing responsibilities.
Request a project estimateCall (512) 948-5922 • Email josh@addrac-construction.com
Sources and further reading
Public guidance checked October 10, 2026. Product instructions and project-specific requirements govern the final design.
Homeowner planning guidance for Austin, Cedar Park, Leander, Georgetown, Liberty Hill, Lago Vista, Jonestown, and Dripping Springs. Code requirements, climate conditions, existing construction, and product approvals vary. The comparisons and clearly labeled examples are not ADDRAC bids, performance guarantees, or a claim of certification.