How to Fill Out and Submit a Blower Door Test Form

A blower door test form is the written report a certified tester signs and submits to your local building department to document that a new or renovated home meets the air leakage limit in the energy code. Under the 2021 International Energy Conservation Code, section R402.4.1.2 requires that written report, signed by the party who conducted the test, before the code official can issue a certificate of occupancy.¹ Most building departments publish their own version of the form or accept a standard format that captures the same data. A rejected or incomplete form stalls the final inspection, which can hold up closing on a construction loan or sale, so the details matter.

What the Form Has to Contain

Every blower door test form collects two kinds of information: facts about the building and facts about the test itself.

The building section starts with the property address and the active building permit number. If those do not match the department’s records, the form gets kicked back before anyone looks at the leakage numbers. The form then asks for the total conditioned volume of the house in cubic feet, the total surface area of the building envelope, and the foundation type (slab, crawlspace, or basement), because foundation type affects how volume is calculated. These numbers feed the air leakage math, so an error here produces a wrong pass/fail result.

The test section records the measured air leakage rate at 50 Pascals of pressure in cubic feet per minute (CFM50) and the converted air changes per hour at 50 Pascals (ACH50). Most forms have a dedicated field where the tester shows the ACH50 calculation. The form also asks for the brand, model, and serial number of the blower door fan and manometer, plus the date of the most recent calibration. If calibration is overdue or undocumented, an inspector can reject the results outright.

The last required element is the signature of the person who ran the test, with their certification number.

The Number the Form Has to Beat

The maximum allowable air leakage depends on which edition of the IECC your jurisdiction has adopted and the building’s climate zone. Most jurisdictions currently enforce the 2021 IECC, though some have moved to the 2024 edition. Confirm the edition and any local amendments with your building department before testing.

2021 IECC Limits

Under the prescriptive compliance path in Section R402.4.1.3:

Climate Zones 0, 1, and 2: no more than 5.0 ACH50.
Climate Zones 3 through 8: no more than 3.0 ACH50.

Regardless of climate zone, no building can exceed 5.0 ACH50 or 0.28 CFM per square foot of enclosure area under any compliance path. For attached dwelling units or homes with 1,500 square feet or less of conditioned floor area, a slightly relaxed limit of 0.30 CFM per square foot applies when tested individually.¹

2024 IECC Limits

The 2024 code tightens the prescriptive path:

Climate Zones 0, 1, and 2: no more than 4.0 ACH50.
Climate Zones 3 through 5: no more than 3.0 ACH50.
Climate Zones 6 through 8: no more than 2.5 ACH50.

Under the performance or ERI compliance paths, the ceiling is 4.0 ACH50 or 0.22 CFM per square foot of building thermal envelope area in all zones.²

If the Project Is Chasing a Voluntary Label

Projects pursuing ENERGY STAR or DOE Zero Energy Ready Home certification have tighter targets than the base code. Under ENERGY STAR National Version 3.2, the home must hit 4.0 ACH50 or lower. Version 3.3, which applies to homes permitted on or after January 1, 2027, drops the limit to 3.5 ACH50.³ DOE Zero Energy Ready Home layers additional requirements on top of ENERGY STAR, verified by a RESNET-certified rater through at least two inspections, one at pre-drywall and one at final.⁴ A code-compliant form does not automatically satisfy these programs; the rater fills out their own documentation.

Who Is Allowed to Sign

The IECC states that where the code official requires testing, it must be conducted by an “approved third party,” and the written report must be signed by the person who performed the test.¹ What counts as approved depends on the jurisdiction, but two credentials cover almost every case.

The Building Performance Institute’s Infiltration and Duct Leakage (IDL) certification specifically authorizes holders to perform blower door tests that meet IECC requirements and conform to ASTM E779 and E1554-07. The certification requires a 90-minute hands-on field exam with a passing score of 85 percent or higher, and holders must recertify every three years, either by retaking the field exam or by demonstrating qualifying work experience.⁵

RESNET-certified Home Energy Raters are also authorized to perform blower door tests as part of producing a home energy rating, and this is the standard credential on projects pursuing ENERGY STAR or DOE Zero Energy Ready Home certification.⁶ Licensed engineers and architects may have standing to sign in some municipalities. Confirm with the building department before assuming it will accept them.

Preparing the Building Before the Tester Arrives

The form only means something if the building was in the right condition during the test. The IECC allows testing any time after all penetrations through the building thermal envelope have been sealed, which in practice means after drywall is finished and exterior cladding, windows, and doors are installed.¹ The code also sets what must be open or closed:

Exterior windows and doors, fireplace and stove doors: closed but not sealed (weatherstripping only, no tape).
All dampers, including exhaust, intake, makeup air, backdraft, and flue: closed but not sealed.
Interior doors: open.
Exterior and interior terminations for continuous ventilation systems: sealed.
Heating and cooling systems: off.
All supply and return registers: fully open.

Beyond the code conditions, practical readiness matters. Attic hatches should sit on weatherstripping and latch down. Bath fans and range hoods should be fully installed, not roughed in. Outlet covers and light fixtures need to be in place, and floor coverings down. Nobody should enter or exit during the test, since opening an exterior door invalidates the reading.

Submitting the Completed Form

Once the certified tester signs the form, it goes to the local building department tied to the active permit. Many departments accept PDF uploads through a digital permit portal; others still require a physical copy delivered in person during business hours. Either way, verify that the permit number on the form matches the department’s records. A mismatch is the fastest way to get the submission bounced without review.

The building department reviews the form to confirm the test results fall within the allowable leakage rate, the tester’s credentials are current, and all required fields are filled in. Turnaround depends on the jurisdiction and the department’s backlog. After approval, the project clears energy verification and becomes eligible for the final inspection. Without a passing blower door test on file, most jurisdictions will not issue a certificate of occupancy, which means the building cannot be legally occupied and any pending sale or loan closing stalls until the paperwork is complete.

If the Number on the Form Is Too High

A failed test is not the end of the project; it means more air sealing, then a retest. The report shows the measured ACH50, which tells the builder how far from the target the building is. The general contractor or insulation contractor seals the leak sources, and the tester returns for a second test. The cycle repeats until the home passes. Retest fees are usually lower than the initial test because the tester already has the building volume and baseline data.

The leak sources that cause most failures are familiar ones: bottom plate to subfloor connections, duct and plumbing penetrations, electrical panels and wiring, attic hatches, recessed lights and bath fans, dead spaces behind tubs and fireplaces, window and door casings, and spots where trades cut through a sealed air barrier for outlets, pipes, or drywall patches without resealing. Foam fills larger gaps, caulk handles smaller ones. Walking the house with a flashlight and a can of foam before calling the tester back is cheaper than paying for a second failure.

Liability for the Person Who Signs

The signature on the form carries professional liability for the accuracy of the numbers. Submitting fabricated data or results from improperly calibrated equipment is a code enforcement matter, not just an ethics issue. Building departments treat falsified compliance documents the same way they treat unpermitted work; enforcement typically starts with an administrative action and can escalate to civil or criminal prosecution.⁷ A tester who signs off on a building that does not actually meet the leakage threshold risks losing their BPI or RESNET certification, and the owner may face mandatory retesting, permit revocation, or denial of the certificate of occupancy until a legitimate test is completed and filed.

1
International Code Council. 2021 International Energy Conservation Code – Chapter 4 RE Residential Energy Efficiency
2
International Code Council. 2024 International Energy Conservation Code – Chapter 4 RE Residential Energy Efficiency
3
Energy Star. ENERGY STAR Single-Family New Homes National Rater Field Checklist Rev 14
4
Department of Energy. DOE Zero Energy Ready Home Single Family Homes National Program Requirements
5
Building Performance Institute, Inc. Infiltration and Duct Leakage
6
RESNET. Amendment Rater Categories of Certification
7
Los Angeles County Building and Safety. Code Enforcement