High-Performance Homes In New Zealand A Survey On The Influence Of The User Behaviour And Its Effects

The number of High-Performance houses in New Zealand has been increasing since the first Homestar rated home was built in 2012. Certified High-Performance Homes can be certified as either Passive House, Homestar, Superhome, or built to a higher standard than what the New Zealand Building Code requires, but not rated under a scheme. Passive House seeks for the house to be thermally comfortable all year round. Homestar seeks an overall sustainable approach, including construction waste and water use, but other factors can help the rating. Finally, the Superhome Movement focuses on a healthy home and design quality. Historically, New Zealand homes built to earlier versions of the New Zealand Building Code were typically cold, draughty and damp. Household Energy End-use Project (HEEP) by Isaacs et al. in 2010 found that the average temperatures in homes were typically around 14°C, consistent with how New Zealand homes are heated, by heating the living room a few hours every evening. The households who participated in this research are not consistent with the New Zealand housing stock as they have exceeded the minimum requirements of the New Zealand Building Code. This paper aimed to explore what the designers and users expected from their High-Performance houses and if their understanding of it influenced the performance of the house. Designers and house occupiers of 9 High-Performance houses were interviewed and asked questions regarding their house's functionality and behaviour. All the participating houses have a mechanical ventilation unit, double or triple glazed windows, as well as higher insulation in walls, roofs and subfloor than required in the New Zealand Building Code. Photovoltaic Panels were present in 4 of the participating houses, 2 of these houses had energy storage systems that allowed the users to store excess harvested energy from the panels. 46% of the participants installed additional building services after occupancy, with a space heater being the most common addition. The results where positive; most of the occupiers where able to maximise their house performance potentials and all the participants understood the systems their house had. The primary motivation of the participants was to build a healthy and thermally comfortable house. All the participants would build a High-Performance house again if given the opportunity. A Design Guide was formulated for future build commissioners and designers to recommend specification solutions to achieve a High-Performance house. Currently, all the participating homeowners have the knowledge to potentialize their house efficiency, as they were the commissioners. In the future, this might shift once more High-Performance houses get introduced into the New Zealand housing stock.