With consent hopefully days away, we finalise the details for the ventilation system. We’re using a Passiv Haus certified system from Germany, called Zhender.
The Zhender system will bring in fresh air from outside, and pass it through a heat exchanger venting warm/humid air to the inside – but keeping the energy in the home. This is a balanced system, and quite different from the common Positive Pressure systems which often force air in from your attic into the home, and force the warm air outside. The system we have chosen has hard ducting, not the flexible type which can trap dust and dirt, and are impossible to clean, and has a retail value of around $14,000+GST, plus another couple of thousand for professional installation and commissioning. In fact, you can’t buy these “out of a box”, as the airflow has to be properly balanced. In some respects, it’s the heart of the home and will ensure excellent air quality, which we’ll be monitoring with CO2 and humidity sensors thanks to the assistance from the University of Auckland.
Click here for the designs which show where the system extracts the air (bathrooms, laundries, kitchen) and where it feeds it back in again. Being completely sealed from the outside, we maintain our air-tightness.
Other documents on the system you can download:
ComfoAir CA550 (note we’re installing the slightly smaller ComfoAir 350).