The Passive House system is an innovative, systems Based, sustainable approach to closing the structural gap between expected and actual occupancy of commercial buildings. This innovative building approach has been adopted in New Zealand by building owners and operators since the early 1990s. The first-ever Passive House property in New Zealand was completed in Auckland last year. One of the principal challenges of any building project is operating within a constrained build environment, where there is limited room for maneuver and design changes as well as easy access for maintenance and servicing. In the case of Passive House developments, the main constraint is the space available for development.
The key to success with this innovative approach is to carefully design the ventilation and heating systems within the structure of the property so that they do not double up on the heating or cooling needs of the occupants of the building. By using high-quality materials, including locally sourced stone walls and brick insulation, passive houses are capable of cooling and heating efficiently even when the overall room temperature is lower than that required for sustaining comfortable living standards. One challenge faced with many buildings with this system is that the resident population is inevitably larger than the minimum requirement for heating. Nevertheless, modern passive house developments are being designed with the resident occupant’s size in mind.
Although New Zealand has enjoyed a period of economic development, it is widely recognized that the country still has some catching up to do when it comes to building and construction standards. As a result, building codes in New Zealand remain relatively less stringent than in other countries. In the past, the main complaint from owners and operators of passive house developments has been that the required heating and cooling were not included in the price of the property. However, this issue is no longer a fundamental problem, as the first certified house standard in New Zealand has been incorporated into the law. This means that almost all Passive House developments are required to include a comprehensive heating and cooling package, which will obviously reduce the overall cost of the project.
Over the past number of years, the role of passive houses has changed considerably, with increased awareness of their value and practicality for new builds. At the same time, an increasing number of people are recognizing the need for more affordable housing. For these people the attractive lifestyle associated with passive dwelling developments provides a distinct advantage – it delivers living comfort at a reasonable price.
The process of developing a New Zealand project has traditionally been dominated by developers who have focused on the location of the build and the amount of space that they could develop. As a result, the outcome of many new builds has been significantly different from that of traditional builds. New Zealand now has a multi-faceted policy for sustainable buildings, which includes: building energy efficiency, enhancing ventilation and heating and additional insulation. This multi-pronged approach means that the energy efficiency of a building depends not so much on the location of the build but on the design and features of the property itself. With a focus on improving the building’s overall energy performance, this is important in reducing the total cost of the project, as well as improving the lives of residents in the long term.
A key factor for the development of any new build is the consideration of the correct planning criteria, which can vary considerably from area to area. While a property located in wet clay may satisfy the local planning criteria for sustainable buildings, in an urban area where compactness is a major consideration, additional considerations need to be taken into account. In the process of considering planning criteria for passive houses in New Zealand, it is often necessary to employ the services of an expert independent consultant. Independent consultants will be able to offer professional and objective advice to assess the suitability of your proposed property for implementation as a passive house, and based upon this information you can then proceed with the next stages of the planning process.
When obtaining planning permission in New Zealand, you will need to ensure that the location of the building, its orientation with respect to any existing building or structures, as well as any existing vegetation is considered and approved in accordance with the relevant planning criteria. This may include consideration of the use of passive houses as an alternative to traditionally designed homes, including the ability to reduce heating and cooling costs through efficient design and the provision of additional cooling and heating supply air conditioning. It is not uncommon for developers to consider the possibility of providing a mixture of secondary dwellings with open plan’s design, incorporating spaces and outdoor spaces to create a more urban look and feel. While the overall size of any new build structure will be determined by the overall supply of land in your local area, there are options available to reduce the size of a property when planning criteria for inclusion are considered.
In terms of building efficiency, passive houses are often designed to meet the highest standards of thermal mass possible. Modern passive house technologies take full advantage of the best materials and techniques available to deliver the highest levels of insulation, as well as achieving optimal levels of energy efficiency. Thermal mass is the term used to describe the heat that a structure gains from the surrounding environment. Passive houses and their thermal mass allow a high level of passive solar heat to be absorbed into the ground and stored. The heat is then used on a daily basis to warm and cool the house. An increased level of passive solar heat can be achieved by increasing the floor area covered by windows, optimizing natural lighting, installing skylights, venting through the roof, improving insulation, and using a variety of clever techniques.