Healthy homes: Countries and cities around the world are taking action to encourage a more sustainable built environment. Approaches include stronger building codes and standards, as well as tax and other incentives for building developers and owners. The market plays a part when improvements are recognised through increased property value.
The desire to be seen to do the right thing is also a powerful motivator. Voluntary environmental ratings systems and guidelines raise public awareness of sustainable building practices and can lead to more formal changes such as the Auckland Draft Unitary Plan.
In North America, LEED for Homes is a voluntary rating tool for new single and small multi-family homes. It is designed to maximise fresh air indoors and minimise exposure to airborne toxins and pollutants. On average, LEED-certified homes use 20 to 30 per cent less energy than a home built to code.
LEED for Neighbourhoods offers pointers for sustainable design on a larger scale, taking in walkability and density of neighborhoods, ease of access to public transportation, stores, and civic institutions, preservation and improvement of ecologically valuable land, and neighbourhood-wide energy sources.
One of the schemes which has received some publicity is Passiv Haus, developed in Germany in 1996 for new homes. Its goal is reducing the housing sector's carbon emissions to a scientifically-justified level with strict performance-based requirements for air leakage, heating and cooling, and overall energy use.
It typically reduces energy consumption by 80 per cent compared to standard construction, making it economical to use renewable energy to meet the remaining demand. However the system is developed for temperatures as low as minus 15, so it has limited application here.
The United Kingdom has the Code for Sustainable Homes for rating and certifying the environmental performance of new homes. Like Homestar, it looks at energy and CO2 emissions, water, materials, surface water run-off, health and well-being, pollution, management and ecology.
Australia's national rating system NABERS measures similar factors, rating the energy and water use of Australian homes from 0 to 5 stars.
In Canada, the voluntary EnerGuide Rating System for measuring the energy performance of new and existing homes is often used as a requirement to participate in incentive programs geared towards the residential sector, such as ecoENERGY Retrofit-Homes subsidies.
At a city level, Vancouver has a Home Energy Loan Program to finance energy efficiency upgrades which are paid back through the utility bill. The loan stays with the house if it is sold. The British Columbia government now wants to make the scheme province-wide.