'Green' homes

Protecting our environment by building with eco-friendly materials and systems has become integral in the design of modern homes. We look at some of the options and point you to further information.

Protecting the environment

Building ‘green’ or ‘eco-friendly’ homes means taking an approach that has minimal impact on the environment. This includes:

Choosing sustainable building materials that do not deplete the natural environment more than necessary, for example, using plantation-grown timbers and recyclable building materials.
Improving indoor air quality by choosing paints with low volatile organic compounds.
Designing for sufficient airflow to lower the need for mechanical ventilation and to stop the growth of unhealthy moulds.
Using passive solar energy where possible by placement of the house and good house design.
Using water economically – installing a tank to collect rainwater for irrigation and flushing the toilet, and installing systems to recycle waste water.
Using passive design for ventilation and cooling.

For more information about managing sewage and waste water to lessen the impact on the environment and to save water, have a look at waste water management information on the Ministry for the Environment website which includes:

Water-saving practices in and around the home.
Choice of household products that will enter the waste water stream.
The different types of waste water and how it can be minimised and reused.
Characteristics of different toilet designs, including composting toilets.

Eco-housing

The concept of ‘eco-housing’ is being developed in some areas in New Zealand. The main principles of the scheme include:

Integration of the buildings with the site to maximise sunlight.
Design for energy efficiency and natural climate control using passive solar design.
Building materials and components chosen to minimise embodied energy content, toxicity and environmental impact, and to maximise durability and recyclability.
Rainwater collection for household and garden use, and on-site stormwater and waste water treatment where possible.
Solar water heaters to provide the bulk of hot water needs.
The incorporation of other renewable energy technology where appropriate.
Clustering of buildings to allow sufficient common land for productive and edible landscaping and recreational spaces.
Comprehensive site design based on permaculture principles to include productive landscaping and organic gardening principles.

For more information have a look at Earthsong Eco-Neighbourhood.

Further information – BRANZ

The Homestar rating tool provides a quick and easy assessment of your home’s sustainability. You can find it at www.homestar.org.nz.

BRANZ has produced two useful publications. The first is Easy Guide to Eco-Building – Design, Build and Live with the Environment. It has lots of ideas for building compatibly with the environment, such as positioning the house for solar energy, and saving water. It also has a comprehensive list of other material and resource links.

The second publication is The Easy Guide to Being a Climate Friendly Kiwi. This guide talks about greenhouse gases and global warming, and gives some options for reducing emissions in the home, for example by insulating hot water cylinders and choosing energy efficient appliances, and planting trees and shrubs.

You can download both publications from the BRANZ website in the ‘Books for Building Trades’ and ‘Books for Home Owners’ section or contact BRANZ for a free copy.

Several local councils provide an eco design advisor service. See www.ecodesignadvisor.org.nz.

Saving energy

The Energy Efficiency and Conservation Authority (EECA) has developed a website on how to save energy at home and work. It contains useful, easy to read information on the ways you can save energy. Visit www.energywise.govt.nz.

Case study

Belinda and her husband have a history of renovating and know a lot about what features and materials are available.

Here are some of their tips. They:

Buy mid-range products in areas such as plumbing as they are more stylish, usually more reliable, and often on sale or discountable (if you use the same firm for all the products).
Always seek council advice on what is needed to meet requirements, (often against the advice of the plumber or builder) and use a variety of different types of insulation in the house.
Put a solarium in the windy south-east corner of the house, with a concrete floor to capture the heat - this has probably added two degrees but it feels like more.
Use recycled windows and doors and spend time hunting sales and getting quotes from rival companies which gives some bargaining power.
Use roofing that does not need painting when it is a steep roof
Lag the pipes and replace the hot-water cylinder for gas. The gas cylinder saves space and gasfitters can be easier to find than plumbers and electricians.
Use energy light bulbs, which are more expensive to buy, but last very much longer and save money in power.
Use thick black polythene on the ground for underfloor insulation.
Use tile sheets in the bathrooms as they are easy to install and there is no grouting to clean - Belinda advises that when using any silicon product you should check that it has anti-mildew properties to stop it developing mildew spots, as it is difficult to dig out and replace later.