Residential testing fan installed in doorway — Residential Testing Fan — doorway pressurisation setup.

Residential Air Tightness Testing

NSAI-certified blower door testing for new and existing homes throughout Ireland. Verify Part L compliance, support Part F ventilation design, and improve BER performance by identifying and fixing uncontrolled air leakage.

NSAI Certified

What we measure & the targets

A calibrated fan is temporarily mounted in a doorway to pressurise and depressurise the dwelling. We measure the air permeability of the envelope at a pressure difference of 50 Pa, expressed as m³/(h·m²) @50Pa (q₅₀).

Regulatory target: ≤ 5 m³/(h·m²) @50Pa for new dwellings.
Design ambition: many designers aim for ≤ 3 m³/(h·m²) @50Pa.
High-performance: Passive House benchmark ~ 0.6 ACH@50Pa.

Rule of thumb (for context)

To estimate typical air changes under real conditions, a simple field heuristic is ACH_nat ≈ q₅₀ ÷ 20. This is an indicative guide only; design/verification is based on the measured q₅₀.

How the test works

Preparation: external doors/windows fitted; obvious penetrations sealed; traps primed.
Setup: blower door fan & manometer installed in a suitable doorway.
Runs: pressurisation and depressurisation at multiple pressure steps; data logged.
Leak finding: smoke/thermal and hand checks at junctions while the fan runs.
Result & report: q₅₀ value with recommendations and certificate.

Readiness checklist

All external doors/windows fitted and closable
Trickle vents/MEV/MVHR terminals accessible (for temporary sealing/balancing as appropriate)
Waste traps primed; chimneys/flues sealed per method statement
HVAC off and dampers open/closed as required by the test method
Safe access to all rooms; power available for test equipment

Typical leakage paths we target

Window/door perimeters, sills & thresholds

Attic hatches and service risers

Joist ends into masonry and wall-floor junctions

Socket back-boxes and service penetrations

Soil/waste penetrations and boiler/plant openings

Roof-wall and ceiling-wall junctions

Ventilation Validation (Part F)

Homes achieving permeability < 3 m³/(h·m²) require mechanical ventilation. We measure supply/extract terminal flows, balance systems, and provide validation certificates in line with TGD F.

Flow rate measurements per room/outlet
Balancing and commissioning records
NSAI-compliant validation certificate

Documentation & deliverables

Method statement and calibration certificates (on request)
On-site test logs and pressure-flow data
q50 air permeability result and certificate
Leakage map / recommendations for sealing

Book your residential air tightness test

Share house type, drawings (if available), target permeability, and preferred dates. We’ll confirm method and schedule.