Design without thermal bridges: In winter, the heat inside a house will follow the path of least resistance
to the outside of the house. This path is known as a "thermal bridge." A thermal bridge can be visualised as a
kind of pipeline for heat-loss from inside a house to the colder air outside.
Conventional homes offer plenty of such bridges, in the form of inefficient window frames, poorly designed walls, ceilings and floors/foundations. Passive house construction eliminates them through superior design.
For example, typical aluminium window-frames offered by New Zealand glass retailers, have continuous aluminium metal contact from the interior to the exterior house surfaces, Aluminium is one of the most highly comductive metal known, after gold and copper. Such alumimium frames rob the warm house air of its heat and conduct it outside to warm the rest of the world.
Modern window frames for passive houses are made using new and exciting timber technology; and if they use aluminium at all, the conductivity path from interior to exterior surfaces is broken. Some models of windows are made using low-conductivity plastics.
Similarly, customary house construction in timber and concrete, as well as the steel-framed houses being offered to the public in 2011 has many thermal bridges incorporated in the design, manufacture and installation. These designs quite simply rob the house owners of the expensive heat they purchase, especially in winter.
The wall structural elements of passive houses in New Zealand are likely to be made from sustainably produced timber assembled in the form of an I-beam, thus greatly reducing energy transmission through the wall structure, and condensation of moisture inside the walls at the location of framing elements.
Timber is the most sustainably produced raw material known to man, and it is with pride that passive houses in New Zealand built to incorporate timber to the extent that they do.
Would you like to see a passive house in New Zealand now?
You can follow the blog of the first build at
New Zealand's first Passive house blog-spot
Another NZ passive-house is documented on-line, on facebook. If you are a facebook user, you should have no problems viewing these pages.
A New Zealand Passive house set of informative pages
A New Zealand Passive house - the base page
Congratulations to Brooke the Architect (MOAA Architects) for what looks like a thorough job, and likewise the builder for following instructions so well. Lots of construction detail in here.
Links to pages about the seven precepts of Passive House design.
Very efficient Insulation
No thermal bridges
Passive solar gain
Prices / costs