BEO Science — Airtightness Testing
Blower door testing across NZ —
ATTMA accredited, ISO 9972 Method 1
Pressure-based airtightness testing for residential, commercial, and Passive House projects. We measure what the building actually leaks — not what the drawings say it should. Auckland, Wellington, Christchurch, Queenstown, and across the North Island.
ATTMA Accredited
ISO 9972 Method 1
Residential
Commercial
Passive House
North Island · South Island
Book a test →
What Airtightness Testing Is
A blower door test measures what actually leaks — not what the specification assumes
Every building has a designed airtightness level. The blower door test finds out what was actually achieved. A calibrated fan is installed in an exterior door, the building is pressurised and depressurised to 50 Pascals, and the airflow required to maintain that pressure differential is measured. That figure — expressed as air changes per hour at 50 Pa (ACH@50) for residential, or air permeability q50 in m³/(h·m²) for commercial — tells you how leaky the building is under a standardised pressure condition.
The gap between specification and reality is where the value of testing lies. Airtightness membranes get punctured, sealed penetrations get added later, junctions don't get taped — and none of that shows up until the fan is running. A pre-line test catches it while remediation is still cheap. A final test confirms the result for certification, compliance, or handover.
What you find in a test you won't find in an inspection
Leakage paths are often invisible — behind linings, above ceilings, through service penetrations that were sealed and then reopened. Pressure testing finds them regardless of where they are.
Pre-line testing is significantly cheaper than post-completion
A test before linings go up allows leakage paths to be identified and sealed while they're still accessible. The same repair after lining-out means cutting, patching, and repainting. The test cost is the same either way.
Airtightness affects energy demand, moisture risk, and comfort
Air leakage bypasses both insulation and ventilation. An airtight building uses less energy to heat and cool, has better control over internal moisture levels, and delivers more consistent comfort. MVHR efficiency depends on it.
Certification requires a witnessed, documented test result
Passive House, Homestar, Green Star, and NCC compliance all require a test result from an accredited tester following ISO 9972 Method 1. An assumed result or an unwitnessed test won't satisfy any of them.
Testing Services
Residential, commercial, and Passive House — one accredited team
Residential Blower Door Testing
For new homes, apartments, and retrofit projects. Results reported as ACH@50 Pa — the standard metric for residential airtightness compliance, Homestar ratings, and Passive House certification.
- New builds and major renovations
- Pre-line test — before linings are installed
- Final test — for certification or handover
- Homestar and Passive House compliance reporting
- Leakage identification service where required
Commercial Blower Door Testing
For offices, retail, warehouses, and mixed-use commercial buildings. Results reported as air permeability q50 m³/(h·m²) — the standard metric for commercial airtightness compliance and Green Star ratings.
- ATTMA TSL1 and TSL2 testing protocols
- Multi-fan testing for large buildings
- Green Star and NABERS airtightness credits
- NCC Section J compliance testing
- Method statement and pre-test consultation included
Passive House Airtightness Testing
Passive House certification requires a blower door test result ≤ 0.6 ACH@50 Pa, carried out to ISO 9972 Method 1 with intentional openings sealed. We carry out both the pre-certification shakedown test and the final certification test.
- ISO 9972 Method 1 — intentional openings sealed
- Result formatted for PHPP and PHI certification submission
- Pre-line shakedown test to identify and resolve leakage early
- Works with any Passive House certifier
- See our Passive House design service →
Shakedown Testing
A pre-line or pre-completion pressure test carried out before finishing works are installed — while leakage points are still accessible. Not a certification test, but the most cost-effective way to ensure the final test passes.
- Carried out before linings, ceilings, or cladding are installed
- Smoke or tracer used to locate specific leakage paths
- Remediation guidance provided on site
- Optional re-test to confirm remediation
- Recommended for all high-performance and Passive House projects
Green Star airtightness — ATTMA L2 testing
Green Star projects require ATTMA Level 2 testing methodology and a Method Statement submitted to the rating body. This is a separate, more complex scope from standard blower door testing.
See Green Star L2 service →
How We Test
The test process — from preparation to report
01
Pre-test preparation and boundary confirmation
Before the test, we confirm the test boundary — the envelope being tested — and identify all intentional openings that need to be temporarily sealed (ventilation terminals, trickle vents, exhaust points). For Method 1 testing (Passive House and certification), all intentional openings are sealed. For Method 3 (indicative testing), they are left in normal condition. We confirm the method and boundary with the client or design team before the test day.
02
Fan installation and pressure test
A calibrated Minneapolis BlowerDoor or Retrotec fan system is installed in the primary access door. The building is pressurised and depressurised across a range of pressure differentials, typically from 10 to 70 Pa in both directions. Airflow rates at each pressure step are recorded. The full bidirectional test takes approximately one to two hours depending on building size and complexity.
03
Leakage identification (where required)
Under pressurisation, leakage paths can be identified using smoke, thermal imaging, or tracer techniques. For shakedown tests and any test that returns an unexpected result, we carry out a leakage walk to identify and document specific problem areas. This gives the contractor a clear remediation scope rather than a fail result with no direction.
04
Result calculation and report
Results are calculated from the measured airflow data using TECTITE Express or equivalent certified software. For residential projects, results are reported as n50 (ACH@50 Pa). For commercial, as q50 (m³/h/m²). Reports include the test method, equipment calibration reference, measured data, calculated result, and pass/fail assessment against the applicable standard. Reports are issued within one to two working days of the test.
What you receive
- ATTMA-compliant test report with full data — method, equipment, results
- n50 (ACH@50) for residential · q50 (m³/h/m²) for commercial
- Pass/fail assessment against the applicable standard or certification target
- Leakage point schedule where identification was carried out
- PHPP-formatted result for Passive House projects
- Report issued within 1–2 working days
Standards & Targets
What the result needs to meet
| Standard / Certification | Metric | Required result |
|---|---|---|
| Passive House Classic | n50 (ACH@50 Pa) | ≤ 0.6 ACH@50 |
| PHI Low Energy Building | n50 (ACH@50 Pa) | ≤ 1.0 ACH@50 |
| EnerPHit | n50 (ACH@50 Pa) | ≤ 1.0 ACH@50 |
| Homestar v4 | n50 (ACH@50 Pa) | ≤ 3.0 for 6 Star · ≤ 1.5 for 7–10 Star |
| Green Star NZ | q50 m³/(h·m²) | ATTMA TSL2 — credit-dependent |
| NCC / H1/VM1 (NZ) | ACH@50 or design input | As modelled — no mandatory threshold |
Coverage
North Island: Auckland, Hamilton, Tauranga, Wellington, Palmerston North, and surrounding regions — our most frequently tested area. South Island: Christchurch, Queenstown, and Otago. Travel to other regions by arrangement — contact us to confirm availability and travel costs for your location and programme.
"10 out of 10 — BEO has gone far beyond their initial involvement, providing ongoing support in a very timely manner and helping out in every aspect of the project."
— Client, Residential Project
FAQ
Common questions
When in the build should the test be carried out?
For maximum value: a shakedown test before linings are installed, and a final test after all services penetrations are sealed and the building is in its normal as-built condition. The pre-line test finds problems while they're accessible and cheap to fix. The final test confirms the result for certification or handover. For projects without a performance target, a single final test is standard.
What's the difference between Method 1 and Method 3?
ISO 9972 defines several test methods by how intentional openings are treated. Method 1 — required for Passive House certification — seals all intentional openings (ventilation terminals, trickle vents, extract points) before the test. Method 3 leaves intentional openings in their normal operating condition. Method 1 gives a result for the building envelope alone; Method 3 includes leakage through the ventilation system. Most certification pathways require Method 1.
What if the building fails?
A fail result means the measured leakage exceeds the target — it doesn't mean the building can't be remediated. We provide leakage identification to locate specific problem areas under pressurisation, and remediation guidance on what needs to be sealed. Once sealing work is complete, a retest confirms whether the target has been achieved. Early-stage shakedown testing significantly reduces the likelihood of a fail at final test.
Do you test across the North Island?
Yes — the North Island is our most active region. We test regularly in Auckland, Hamilton, Tauranga, Wellington, and surrounding areas. We can usually schedule within two to three weeks for North Island locations. Contact us with your programme and location and we'll confirm availability.
Is ATTMA accreditation required for certification testing?
For Passive House certification (PHI), the test must be carried out by a qualified tester following ISO 9972. ATTMA accreditation is recognised by PHI and satisfies this requirement. For Green Star, ATTMA Level 2 accreditation is specifically required — see our Green Star ATTMA L2 service. For Homestar and NCC compliance, an ATTMA-accredited result is accepted by all major rating bodies in NZ.
Can you test large or multi-unit commercial buildings?
Yes. Large commercial buildings may require multiple fans operating simultaneously to achieve and maintain the test pressure differential across the full building envelope. We use multi-fan setups for large floor plates and can coordinate with the building team on fan placement and temporary sealing of internal partitions. Contact us to discuss the specific requirements for your building size and configuration.