A Passive House (Passivhaus) is a building, for which thermal comfort (ISO 7730) can be achieved solely by post-heating or post-cooling of the fresh air mass, which is required to achieve sufficient indoor air quality conditions – without the need for additional recirculation of air. This means a building, built to Passivhaus standard, with an MVHR system installed. Passivhaus characteristics generally consist of excellent levels of comfort, consistent fresh air throughout the building, improved indoor air quality and hygiene and extremely low energy costs.
Current Air Tightness Testing Standards for Passivhaus
The test standard for low energy buildings is ATTMA TSL4 (2018), which was written in conjunction with the Passivhaus Trust. This is generally based around a combination of TSL1 and TSL2 with a few tweaks that are going to be implemented when these standards are next updated.
Can any building just be Passivhaus if I seal it up really well?
No. For an architect to be able to specify suitable products in their designs, to meet Passivhaus standards, they must refer to the database of certified components as dictated by the Passivhaus Institute (PHI). The database has the following categories:
Opaque building envelope (wall and construction systems, floor slab insulation, flue systems, façade anchors, air tightness systems).
Building services (ventilation systems, heat pumps, warm water heat recovery).
How is my PassivHaus air test conducted?
There are a few differences in testing when conducting a Passivhaus test. Our engineer will prepare your building as per Passivhaus requirements. This follows the normal building preparation for a standard Air Tightness Test however the only temporary sealing required is the vents for your MVHR system. Any other vents are to be closed only. Our engineer will then carry out a depressurisation test and obtain results. The rig is then reversed, and a pressurisation test is carried out and results are obtained again. Once these results are put together it will create an ‘Air Changes Per Hour’ (N50) result by taking the mean of the two. (eg. Depressurisation N50 is 0.5 and Pressurisation N50 is 0.6 meaning the final N50 is 0.55). Air Changes Per Hour is the air leakage rate per internal volume at the test reference pressure differential across the building envelope.
It is likely you will require more than one Passivhaus test throughout the build process in order to track your progress. It is recommended you have at least three tests. (One after the shell has been built, one mid-way through the build and one at completion). Depending on issues that arise throughout the build it may be necessary to have more. During the interim tests it is acceptable to temporary seal other items as necessary, but these must be declared and will never be counted as your final test, even if the result comes in as required. During the interim tests we can advise where further sealing is required and where leakage is occurring. Your Passivhaus test should take approximately 60 minutes to complete in total.
Just like every other dwelling or commercial premises it is highly likely your Passivhaus project will also require a standard Air Tightness Test in order to determine an Air Permeability Score. This will be for building regulation sign off. This can be completed at the same time as your final Passivhaus test and separate certification is produced for this.
Let Energytest guide you
At Energytest we are experts in providing professional advice on the design and specification of low energy and sustainable buildings, offering practical solutions to achieving compliance.
We have a team of professionally trained consultants that offer nationwide coverage that can guide you smoothly the processes, from concept to completion. Talk to us today how we can help.
This website or its third party tools use cookies, which are necessary to its functioning and required to achieve the purposes illustrated in the privacy policy. If you want to know more or withdraw your consent to all or some of the cookies, please refer to the privacy policy. By closing this banner, scrolling this page, clicking a link or continuing to browse otherwise, you agree to the use of cookies.
