New Construction & Post-Retrofit Performance Verification

Duct Blaster Testing for Code Compliance

A duct blaster isolates and pressurizes the duct system independently of the building envelope, producing a CFM25 leakage number at 25 Pascals of test pressure. That number is reported two ways — total duct leakage, and leakage specifically to outside the conditioned space, since a duct that leaks entirely within a conditioned basement doesn't waste energy the same way one that leaks into an unconditioned attic does.

Most current energy codes cap allowable duct leakage per hundred square feet of conditioned floor area, and the threshold tightens further if ducts run entirely inside conditioned space versus partly through an attic or crawlspace. A duct blaster test is the only way to prove a system falls under that threshold rather than estimate it from the installer's workmanship alone — sealed mastic joints can still leak at connections that look fine to the eye but fail under pressure.

We report both numbers separately because they answer different questions for different people. Total leakage tells a code official whether the duct system as a whole meets the airtightness requirement written into the energy code. Leakage to outside tells an HVAC contractor whether conditioned air is actually being lost to an attic, crawlspace, or garage — the leakage that shows up directly on a homeowner's utility bill. A system can pass a total-leakage threshold while still losing a meaningful share of its air to unconditioned space, which is why both figures belong on the same report rather than a single combined score.

Third-Party Verification for ENERGY STAR & IECC

Many jurisdictions and every ENERGY STAR certification path require independent, third-party diagnostic verification rather than builder self-certification. We provide that independent testing and deliver results in a format built for direct submission — CFM50, ACH50, and CFM25 duct leakage documented clearly against the specific code year and compliance path your project is permitted under, whether that's prescriptive, performance, or ERI-based.

Because the testing is performed by a party independent of the construction crew, the results carry the credibility that code officials and program administrators require. We coordinate scheduling directly with your superintendent so testing happens at the right build stage without holding up the trade schedule.

For builders working across multiple jurisdictions, keeping a single testing partner on every lot also standardizes the paperwork. Instead of learning a new report format for every energy rater or code office, you get a consistent test protocol and a consistent document, which makes it faster for reviewers to find the number they're looking for and faster for your office to track which lots have passed and which are still pending a re-test.

Post-Retrofit Re-Testing for Existing Homes

The same duct blaster and blower door protocols we use on new construction apply just as directly after a retrofit on an existing home. Re-testing following insulation and air sealing work generates a documented before/after comparison — the exact evidence utility rebate programs and homeowners both want to see that a sealing project delivered measured, not assumed, results.

A post-retrofit report pairs the original baseline ACH50 or CFM25 number against the re-test result, side by side, with the percentage improvement calculated directly. That single comparison is often the deciding piece of documentation for a utility rebate application, and it's the clearest possible proof to a homeowner that the money spent on sealing and duct work actually changed the house's performance rather than just its comfort on paper.

New Construction & Verification FAQs

Related Diagnostics

New construction verification pairs closely with these diagnostic tests.