Thoughtful, fast-growing force in sustainable consultancy harnessing analytical theory to deliver multiple projects. Rightly gaining national recognition.
Judges, Bristol Property Awards 2025
Passive House is an approach to building design that sets the highest standards of energy efficiency in the world. Ensuring the building envelope is airtight plays a key role in this, requiring more air tightness tests to be carried out using a more rigorous methodology than for standard properties.
Our local passive house air testing engineers are always delighted to work on Passive House projects because the end product – a super energy-efficient, airtight building – has a higher energy performance than a typical property.
Also referred to as “Passivhaus”, or low energy air tightness testing, the main variations between a normal project and a Passive House one include the standards set (you need to achieve far lower air leakage scores), the process followed (the building must be pressurised, then depressurised), and the number of tests required (at least three tests must be carried out along the construction timeline).
Learn more about passivhaus air tightness testing and find answers to common questions in our FAQ section below.
Our expert sustainability surveyors are a team of experienced, friendly, and knowledgeable professionals well-versed in building testing. Get in touch today for a free consultation or competitive quote.
Why work with us?
Experience
Our testing engineers have over 25 years of combined experience, with thousands of tests under our belts.
There is not much we haven’t seen, meaning that we can provide on-site advice on every aspect of air tightness testing.
Quality
We consistently provide exceptional service to help clients pass their air test on the first visit, offering our knowledge to help them find leaks in their buildings and rectify any issues.
If your property is unlikely to pass, we will advise on how to fix this.
Speed
Our office-based staff work hard to book all appointments as quickly as the delivery schedule allows.
95% of all tests take place within two weeks of the initial booking, with the majority of certificates provided within 24 hours of the site visit.
Pricing
Our rate card prices for all services are reviewed regularly, so we’re confident that you won’t find a better service for a better price anywhere else.
If you think you’ve found one, we’ll either beat or match it.
Support
Navigating the complexity of energy efficiency, decarbonisation, and building regulation updates isn’t easy.
We’ve worked hard to explain a range of topics related to Passivhaus air testing in plain English to help non-experts get the information they need.
Get Your Passive House Air Tightness Testing Quote Today!
Looking for a fast and reliable passive house air tightness test in Bristol or nationwide?
Contact us today for a free quote and to discuss your specific project requirements. We offer competitive rates and prioritise fast turnaround times for all our clients.
Passivhaus Air Tightness Testing: Your Questions Answered
We’ve compiled answers to the most common questions about passivhaus air tightness tests to help you navigate this crucial tool for energy efficiency.
What is a Passivhaus (or Passive House)?
Passivhaus is a world-leading standard for building energy-efficient homes. It’s a design and construction methodology that creates ultra-low-energy buildings that require very little energy for heating or cooling. A certified Passivhaus is built with meticulous attention to detail and features super insulation, minimal thermal bridging, and exceptional airtightness to provide maximum comfort with a minimal environmental footprint.
What is the airtightness requirement for a Passivhaus?
The airtightness standard for a Passivhaus is extremely strict. A building must not have more than 0.6 air changes per hour (ACH) when pressurised to 50 Pascals (n50≤0.6 h−1). This is significantly more stringent than the requirements for a standard new build in the UK.
How is a Passivhaus air test different from a standard air test?
While both tests use a blower door fan to measure air leakage, the Passivhaus test is much more rigorous. The key differences are:
– The Target: The airtightness target of 0.6 ACH is far lower and harder to achieve than for a standard build.
– The Method: Passivhaus testing uses ‘Method A’, which measures air changes per hour based on the building’s volume (m3/h.m3 @ 50Pa). Standard UK tests typically use ‘Method B’, which measures air permeability based on the building’s envelope area (m3/h.m2 @ 50 Pa).
– The Procedure: A Passivhaus test requires both a pressurisation test and a depressurisation test to be carried out. The final result is the average of these two figures. The data logging and environmental readings are also more extensive.
How many air tests are needed during a Passivhaus build?
Unlike a standard build which may only have one final test, a Passivhaus project typically requires multiple tests throughout the construction process to ensure it stays on track. It is common to test at least three times:
1. Stage 1: After the initial air barrier is complete.
2. Stage 2: After second-fix works are complete.
3. Stage 3: At completion for final certification.
Testing at these key stages helps to identify and fix leaks early, which is critical for meeting the final target.
What are the different Passivhaus certification levels?
There are three main certification levels, each with increasing requirements for energy efficiency and on-site renewable energy generation:
1. Passivhaus Classic: The foundational level, focused on achieving exceptional airtightness and insulation to minimise energy use.
2. Passivhaus Plus: Builds on the Classic standard by requiring the home to produce as much energy as it consumes through renewable sources.
3. Passivhaus Premium: The highest and most demanding level. The home must generate significantly more energy than it uses, with the potential to be a net contributor to the power grid.
Can existing buildings be retrofitted to a Passivhaus standard?
Yes. For retrofit projects where the original architecture makes meeting the full Passivhaus standard unfeasible, the EnerPHit standard can be used. This is a slightly relaxed but still very challenging standard for achieving exceptional energy efficiency in existing buildings.
