In other blogs I wrote about our sustainability goals and different concepts and definitions of sustainability in the built environment. Over the years different frameworks have been developed to assess sustainability of homes. The best known rating tools for homes are BREEAM (Building Research Establishment Environmental Assessment Method) in the UK, LEED (Leadership in Energy & Environmental Design) in the US and Green Star in Australia. Each of these rating tools have their own specific focuses and categories that they assess a home on.
In the different categories you can score points which add up to a total rating of the building where the best scores for the different frameworks range from outstanding, platinum or 6 star.
Another certification tool is the Living Building Challenge which is a building certification program comprised of seven performance categories called petals developed by the Living Future Institute which besides the usual suspects also rates beauty, equity and education. It is currently the most rigorous certification in buildings with only a limited amount of buildings in the world certified under this label. It also includes a red list of materials to be avoided.
Passive house is another standard with a focus on the energy performance of the building. A blower test to test the airtightness of the home and modeling of the performance are part of the certification.
For New Zealand specific Homestar was developed in 2010 based on international rating tools and adaptation for New Zealand conditions.
For commercial properties like offices there is Green star for the design and construction phase to assess different environmental aspects and NABERSNZ to measure the energy performance during operation.
Homestar rates on Health & Comfort, Energy, Water, Waste, Site and Management.
In each category points can be scored which all total up to a score of 1 to 10 where a score of 4 meets the current building code requirements and 10 stands for world leading self sufficient.
Are we going to certify our home for Homestar, Living building Challenge or Passive house? I don’t think so. I am definitely going to self assess and benchmark against them and see where we would roughly rate but the cost of certification is pretty steep. Homestar certification for example costs around NZ $3500,- . Money I’d rather spend on the house itself. The other thing that I am starting to become more convinced of is the need for affordable housing in New Zealand is more important than achieving the latest state of the art top of the bill in sustainability. So we are not aiming for the highest Homestar rating but for designing and building an “affordable, good and green” home.