The Five Passive House Principles
All five of these principles need to work together to make a Passive House, otherwise it’s just green-wash.
High levels of insulation appropriate for the climate
Depending on whether you live in Auckland, Christchurch or Invercargill your levels of insulation will be ddifferent.
Harley Passive House has the expertise to advise what you need for your house.
Airtightness less than 0.6 air changes per hour
Verified by a blower door test. An airtight building ensures you don’t have unwanted draughts.
The blower door test is a requirement for a Certified Passive House and is an independent verification that the air tightness has been done correctly.
Triple glazed windows
Triple glazed windows that meet the performance required for a Certified Passive House and installed in the right place. The recessed windows help minimise the thermal bridge at the junction of the wall to window frame.
A small thermal bridge multiplied by the distance around all the windows perimeters soon becomes a large value for heat loss.
Certified Passive House Trades People know that a detail like this matters.
Thermal bridge free construction
Here is an example of a thermal bridge model showing the temperature profile where the wall meets the foundation. This is very important in the overall energy balance and for identifying potential condensation risk.
The pictures to the right show the differences between an insulated slab on the left and an un-insulated slab on the right.
Mechanical Ventilation with Heat Recovery (MVHR)
Using a balanced supply and extraction system throughout the house.
The ventilation system not only brings fresh air into the home but is responsible for warming up that incoming air with its heat exchanger. Typically 75-85% of the out going heat is able to be recovered for the running cost of a 50 Watt light bulb.
The living/bedrooms are supplied with fresh air and the wet rooms like the laundry, kitchen, bathroom and toilets are extracted from. This means that any smells or moisture are contained and extracted at their source.