SR369 Retrofit performance measurement of Kotuku Apartments (December 2019)

This is the second of a series of three BRANZ study reports prepared on the upgrading of Wellington City Council's four low-rise Kotuku Apartments, located in the suburb of Kilbirnie, Wellington, New Zealand. This report's focus is on the actual building performance transformation via a suite of in situ experiments executed to quantify aspects related to comfort, cost and liveability.

It was found that, quantitatively, there were marked improvements to whole-building thermal envelope performance in terms of uniformity and a raised level of thermal resistance. However, it was also found that, quantitatively, while there was an improvement for individual apartments to provide thermal comfort, its exact extra level was difficult to determine. The utility of the showers, in terms of flow rate, was improved while still maintaining acceptable water efficiency levels. Lastly, it could not be established whether there were any significant improvements to the background uncontrolled ventilation (i.e. draughts) that is naturally provided by the building, due to shortcomings in the available data.