What does the project involve?

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Nine houses in Papakowhai were selected as case studies, representative of New Zealand homes from the 1960s and early 1970s, a major home building era in New Zealand, with a legacy of about 400,000 homes.  Housing in this era is known to be difficult to retrofit for energy efficiency.

The houses, all owned by the occupiers, are located in a middle income suburb of Porirua, and include a variety of house design and sizes.  Houses with a Rateable Value of more than $410,000 were excluded.

Although the project commenced with early monitoring of the ten houses, one house was subsequently sold and the new homeowners not keen to be part of the project.

Before any changes were made, the nine houses were all monitored for energy and water use, temperature and humidity, and the amount of waste produced. This data was compared to post-renovation data to evaluate the effects of the changes.

In the first part of 2007 the homes were renovated with energy, waste and indoor environment quality improvements.  Each home had a different combination of features installed, to allow comparison of their effectiveness. The aim is to identify the combinations of renovation options which are:

  • the most cost effective
  • easy to implement
  • applicable to a range of house types and regions
  • able to significantly improve how well the homes perform in energy efficiency, water conservation, waste minimisation and indoor environment quality.

The homes were then monitored for 15 months following the renovations to enable a clear comparison between the before and after performance of the homes.


Papakowhai from above

Photo courtesy of BRANZ