Achieving true energy efficiency starts with airtightness. At ARMEEC LTD, we offer expert Passive House Air Leakage Testing to help homeowners, builders, and developers meet the strict 0.6 ACH@50Pa standard of the Passivhaus method.
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Passive House (or Passivhaus) Air Leakage Testing is a highly specialised blower door test that meticulously measures how much air escapes from a building's envelope. Unlike standard Part L building tests, this procedure follows rigorous international guidelines.
The primary goal is to prove your building achieves an ultra-low energy demand. To successfully gain full Passivhaus certification, the building must typically achieve a result of ≤ 0.6 air changes per hour (ACH) at a pressure difference of 50 Pascals (n50). For the EnerPHit standard (retrofits), the target is slightly relaxed to 1.0 ACH.
Whether you're targeting formal certification or simply aiming for the highest tier of energy performance ahead of the 2026 Future Homes Standard, our team ensures your property meets its design goals with precision and care.
Book Your Passivehaus Test Today →An airtight building is the cornerstone of the Passivhaus methodology, eliminating thermal bypass and dramatically cutting energy bills.
It provides the required proof to the Passivhaus Institut that the building’s envelope is genuinely airtight, allowing formal certification.
By eliminating draughts and uncontrolled ventilation, heat loss is minimized, resulting in vastly improved energy efficiency and lower running costs.
An airtight envelope prevents cold draughts and works seamlessly with MVHR systems to maintain a steady, comfortable indoor temperature year-round.
As the UK transitions towards the 2026 Future Homes Standard, meeting these ultra-low targets makes your building environmentally resilient.
Uncontrolled air leakage often carries moisture into the building fabric. Stopping this prevents interstitial condensation and mold growth.
It ensures that the high-quality materials and architectural detailing planned during the design stage were successfully executed on-site.
We partner with you throughout the build, ensuring you don't just test, but successfully pass the rigorous 0.6 ACH target.
We carry out early-stage part-built checks to visually inspect the airtight membrane and spot potential problem areas before walls are closed up.
We use highly calibrated blower door equipment to conduct both pressure and depressurisation tests accurately, in line with Passivhaus standards.
If you're missing the target, we utilize smoke pens and thermal imaging to locate micro-leaks, giving your team immediate advice on how to seal them.
You receive a clear, comprehensive test report (graphing both pressurization and depressurisation cycles) that is fully accepted by Passive House certifiers.
Hitting the Passivhaus standard of 0.6 Air Changes per Hour (ACH) at 50 Pascals is notoriously challenging. It requires a fundamental shift in construction mindset, moving away from 'build tight, ventilate right' to 'build absolutely sealed, ventilate mechanically'.
Standard UK Building Regulations (Part L) currently mandate a maximum air permeability of 8.0 m³/(h.m²) at 50Pa, though many new builds aim for around 3.0 to 5.0 to pass SAP calculations. In contrast, the Passivhaus target is volumetrically based and is roughly equivalent to a standard UK measurement of less than 1.0 m³/(h.m²).
Measures air permeability by dividing the leakage rate by the envelope area (m²). It allows for a relatively porous building envelope, assuming that natural trickle vents will handle the bulk of ventilation.
Measures air changes by dividing the leakage rate by the internal volume (m³). It demands a near-hermetically sealed structure, relying entirely on Mechanical Ventilation with Heat Recovery (MVHR).
Before construction begins, architects must draw a continuous 'Red Line' on their plans representing the airtight boundary. Every single junction, window frame, and service penetration (pipes/wires) that crosses this line must be meticulously taped and sealed using specialized grommets and airtight membranes.
As the UK gears up for the 2026 Future Homes Standard, the gap between standard compliance and Passivhaus is closing. The 2026 regulations will demand significantly tighter building envelopes, effectively forcing the mainstream industry to adopt Passivhaus detailing techniques to eliminate thermal bypass and reduce carbon footprints.
The number one cause of leakage. Specialized expanding foam tapes (like Compriband) must be used between the frame and the airtight layer.
Standard sockets leak air. In a Passivhaus, either airtight back-boxes must be used, or a service void must be built entirely inside the airtight line.
Where timber joists pierce the masonry or membrane, they must be individually wrapped and taped to prevent immense leakage.
An airtight home requires perfect ventilation. Balancing the MVHR system correctly is the critical final step after the airtightness test is passed.
We provide the diagnostics and expertise required to hit the toughest targets.
Everything you need to know about preparing your site and hitting the ultimate 0.6 ACH target.