Extract

Aorangi House is a recently refurbished 12-storey commercial building located in the CBD of Wellington, New Zealand. This paper sets out to investigate the nature of its environmental re-design, and report on its performance in practice in terms of energy consumption and users’ perceptions.

The original building was from the 1970s, fairly typical of its era, and had lain empty since 2005. The refurbishment, which was to house the offices and conference rooms of a firm of consulting engineers, was completed in 2009. The building was one of the first refurbishments to achieve a 5-Star Design rating from the New Zealand Green Building Council. The investigations of its performance followed a year of occupancy.

In terms of its re-design, the design team (Studio Pacific Architects and Beca) aimed to maximise the use of natural ventilation and lighting, replacing the existing windows with double-glazed units, adding 100mm insulation externally to expose existing thermal mass and fixed external solar shading. The mixed-mode system has both manually operated and BMS-controlled windows to provide natural ventilation and cooling, together with a variable refrigerant flow cooling system.

Energy studies carried out over the first two years of operation indicated a good energy performance, with an Area Energy Use Index (AEUI) of 101 kWh/m2.year for the period 2011 to 2012. This compares favourably with a typical AEUI for naturally ventilated New Zealand office buildings of 210 kWh/m2.year.

A PROBE-style Workplace Questionnaire was used to gauge the perceptions of staff to a range of factors (some 50 in total), ranging from temperature and air quality to health and productivity – the full analysis of the user responses is presented. It was found that this building, with a Summary Index of +2.12 (on a -3 to +3 scale) performs particularly well overall from the users’ point of view.

The reasons for this overall excellent performance are discussed, together with specific issues that require further attention from both the designers and the operators of such buildings, and their users.

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