SIPs building are naturally more airtight than a traditional timber framed house.
Proclima product for internal walls, called Intello Plus, however, because of the airtightness of the OSB, all we had to do was use the Tescon Extora tape over each join.
Blower Door Test
Once you’re confident that you’ve sealed up all the gaps in the joins and pentrations through the SIPs, its time to bring in the experts and test the performance of all the technologies.
For this test I called Drew from PassiveTech who specialises in a few technologies to improve the quality of air we breathe, to energy efficient hot water services.
Drew rigged up the blower door instruments, and during the process, walked around with his smoke blower to see if there were any weak points in joins and around windows and doors.
Drew also used his Flir infrared camera to check for leaks or thermal bridges which could be remedied prior to plaster going on.
To achieve passive house accrediation, the house must achieve a minimum of 0.6 air changes per hour (ACH) or fewer at 50 Pascals of pressure.
The outcome for the build was 0.17 ACH which went far beyond the 0.6 minimum.
Mechanical Heat Recovery Ventilation
Because of the airtight nature of the house, with the windows shut the vast majority of the time, it must breathe, otherwise the air inside will become stale, high in CO2 from breathing, and become mouldy.
The best way to tackle this is with a Mechanical Heat Recovery Ventilation (MHRV) system like the Zehnder Q350. Think of it as a smart breathing system for your home that continuously swaps out stale air for fresh air—without losing your indoor warmth.
Here is exactly how it works:
- Extracts Stale Air: The unit quietly pulls damp, stale air out of your kitchen, bathrooms, laundry, and toilets through specialised, anti-static tubing.
- Draws Fresh Air: At the same time, it pulls fresh, clean air from the outside.
- Recycles the Heat: Inside the unit, the two air streams pass right next to each other without ever mixing. The heat from the escaping stale air is transferred to the incoming fresh air at an incredible 96% efficiency.
- Delivers Comfort: This fresh, pre-warmed air is then gently circulated into your bedrooms and living areas.
In short: You get a constant supply of clean, oxygen-rich air throughout the day while retaining 96% of the heat.
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