Providing independent information and links to guidelines and tools to help design and construct sustainable buildings.
Building Rating Schemes/Tools
This section contains information on New Zealand’s building rating tools.
Homestar™ is a New Zealand home rating and advisory tool that examines a broad range of home performance and resource consumption-related issues and is applicable to both new and existing homes.
The tool helps people assess the intrinsic value of their homes using a robust framework adapted from similar tools throughout the world, based around key indicators of warmth, health and resource performance.
A star system is used to indicate the overall performance of the house and ranges from 0–10. A 10-star rated home is an exemplar house across all areas of energy, comfort, health, water, waste, operation, proximity to amenities and material management.
The rating tool has three interactive levels – for homeowners, building professionals and certified Homestar™ assessors.
BRANZ scientists carried out a desktop analysis of 10 Building Code-compliant houses and terraced homes to estimate the additional cost needed to achieve a higher level of Homestar. The designs analysed were selected from actual new buildings at Hobsonville Point.
The research (detailed in Study Report SR391) found that a 6-Homestar dwelling costs approximately 3% more to construct than a typical Building Code-compliant dwelling, and a 7-Homestar dwelling an extra 4%. These additional costs can be reduced when there are a number of similar homes in development.
In return for this increased capital cost, the benefits are lower running costs in the house, higher market value and improved occupant health and comfort.
HomeFit assesses the health, comfort, energy efficiency and safety of homes that have been lived in for some time. (Owners/designers of new homes should use the Homestar tool.)
An assessor goes through a property, looking at insulation, ventilation, heating and energy efficiency. The assessor considers the property’s performance in terms of providing a healthy warm and dry environment. If it meets certain requirements it gets a HomeFit stamp. Homes with a higher level of performance can get a HomeFit Plus rating. People selling or renting out a property can use the rating in their marketing material and advertising.
As well as the assessment service, there is an online check that people can use as a basic guide to a house and how improvements can be made.
The service was developed by the New Zealand Green Building Council with industry input.
There are a number of overseas energy-related tools which have some application in New Zealand, such as the Canadian-based online software programme RETScreen.
RETScreen can be used to evaluate the energy production and savings, life-cycle costs, emission reductions, financial viability and risk for various types of energy efficient and renewable energy technologies (RETs). The software is free to download and the website includes data and case studies. Energy studies include technologies such as wind energy, solar hot water, solar space heating, biomass heating, passive solar heating, ground source heat pumps, photovoltaics and wind energy. Climate data for various locations in New Zealand is available.
Updated: 18 September 2019