The Future of Building Sustainability in New Zealand

In the wake of demands for affordable housing and the increasing threat of climate change, the time for sustainable development is now. New Zealand's building industry is seeing a growing interest in environmentally friendly processes and products. So what exactly is a green building, what are the benefits and how is New Zealand preparing for sustainable building in the future?

What is sustainable/green building?

The concept of the sustainable or green building began in the 1960s. As part of the 'back to nature' concept, energy-conserving housing and office designs were promoted as an environmentally friendly alternative to traditional building design.

Green building is a flexible term used to describe a whole building process from planning to demolition.

Today the definition of green building remains diverse. It refers to the building materials, the processes used to create it and its lasting impact. Each aspect is required to be environmentally responsible and resource-efficient over a building's life-cycle. This includes planning, construction, maintenance, renovation and demolition. Green buildings make particularly efficient use of resources such as energy and water. They also focus on creating healthy, natural environments for people to live and work in.

Benefits of sustainable building

The popularity of green building in New Zealand has soared in recent years, and for good reason. The practice of using sustainable materials, processes and designs have a multitude of benefits for users and owners:

• Cheaper to operate over their lifetime: More efficient use of key resources such as water, land and energy reduces costs. Over a 20-year stretch, the outset cost of building sustainably is repaid around five-six times by operational cost savings alone, according to the NZ Ministry of Environment's Value Case.
• Warm and dry all year-round: The need for energy efficiency drives higher quality insulation and ventilation so a warmer, drier house can be maintained easily.
• Healthier and more comfortable: Improved levels of natural light and clean air alongside warmer and better-insulated conditions are beneficial to occupant health.
• Less environmental impact: A building that is designed, built and operated around sustainable practices helps to conserve both the surrounding environment and that wider afield. In a time of increasing threat to the natural world this is a significant benefit.

The New Zealand situation

For those in the building industry it will come as no surprise to learn that New Zealand is in the midst of a housing crisis. As of 2018, NZ has a calculated housing deficit of 71,000 homes according to the Ministry of Business, Innovation and Employment (MBIE), while more locally Auckland and Canterbury are both in need of 15,000 homes each.

But alongside the need for more houses is a demand for higher quality. New Zealand currently has some of the most inadequately heated and damp housing in the developed world according to the Auckland Regional Public Health Report, and this is having a direct impact on occupant health. The The prevalence of asthma is astoundingly high for a developed nation and seems to be connected with the damp, cold conditions caused by houses lacking insulation.

NZ houses are often damp and poorly insulated.

These concerns combined with increasing alarm around climate change have seen the demand for green buildings in New Zealand grow exponentially. The drive for sustainable construction has also been boosted by the introduction of the Green Star and Homestar rating systems run by the New Zealand Green Building Council (NZGBC). This has given the industry a method of measuring buildings' sustainable features and environmental impact over their life-cycle.

The Green Star rating

One of the main innovations to green building in NZ has been the introduction of the NZ Green Building Council and its Green Star and Homestar rating systems. The newest version of Green Star (version 3) was made effective on January 1, 2018, and acts as a comprehensive, voluntary environmental rating scheme. Stakeholders in property and construction can choose to adopt Green Star as a tool to design, construct and operate building projects more suitably. It also provides a standard rating or score that evaluates the completed building's overall environmental impact.

The rating takes into account nine categories:

• Water
• Energy
• Materials
• Transport
• Indoor Environmental Quality (IEQ)
• Management
• Emissions
• Land use and ecology
• Innovation

Each project is then awarded points that correspond to a Green Star rating. Ratings go from zero to six, with six being world leadership.

The Homestar rating

The Homestar system mirrors Green Star but is designed specifically for NZ homes. A home is rated from six to 10 with a six or higher providing assurance that the home is of overall better quality than typical new houses when built to standard building codes. A 10-star rating means the home is world-leading. The Homestar rating process has two stages: Design and built, which take into account:

• Energy
• Health and comfort
• Water
• Waste
• Materials
• Site
• Home management
• Optional innovation category

Homestar has been particularly popular, with registrations increasing from 670 in 2014 to 6,700 in 2017 according to Andrew Eagles, chief executive of NZGBC. New Zealand residents are increasingly supportive of houses that are of high standard and efficient. It is likely that such ratings will become a standard buyer requirement.

Case study example in NZ

The NZGBC star ratings are challenging and it is still very rare for buildings to achieve the highest scores. To date, there are only five buildings that have achieved a 10 Homestar rating. The first to do so (under Homestar V3 Design) was a Wellington waterfront home designed by Eco Green Homes.

The house included elements such as enhanced daylight from solar-powered skylights, low VOC paints, and high-quality insulation from insulated panel walls and triple glazed windows. There is also an electric car charge point.

At Altus Window Systems we work hard to make our products environmentally friendly. Our energy-efficient Pacific Thermal Suite of windows can add up to 50 per cent more thermal efficiency than double glazing alone.