Renovations are the ideal opportunity to make your house more efficient and sustainable. Try these tips and feel good about your home.

From the design through to the construction of your renovation, opportunities exist to lighten your environmental footprint. These changes can range from short-term aspects (safely managing and recycling building waste, for instance) to long-term improvements in the energy efficiency of your home.

If you're renovating, explore good design: it can save energy, water and money, while creating a more pleasant living space that's also better for your health.

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Every house is different, so the specific ways you can reduce the environmental impact of your renovation and energy use will be different in each case. However, we can offer the following areas of focus, and ideas to assist you in crafting a green renovation.

1. Passive design
2. Water use and re-use
3. Energy efficiency, capture and use
4. Materials selection, use and re-use
5. Minimisation of construction waste

1. Passive Design - Passive design uses the physical orientation of your house and an understanding of the seasonal weather patterns to design a space that requires no heating or cooling to be comfortable all year round. Passive design elements include orientation, insulation, double gazing, thermal mass and airflow.

For example, you might open up the north face of your living space to the winter sun to heat a concrete-slab floor or wall. This utilises orientation and thermal mass to make your house better at capturing and holding heat.

According to the Australian Greenhouse Office, approximately 30% of our household energy bills could be eliminated through intelligent (passive) heating and cooling techniques.

2. Water use and re-use - Renovations provide a unique opportunity to re-engineer your plumbing to suit the water-scarce world in which we live. The specific design of your water system would depend on your needs and the rainfall in your area.

If we look at the four types of water we generally have available, the options for a new approach to water use in the home becomes clearer.

• Mains water - A clean, reliable and chlorinated source of potable (drinkable) water.
• Rainwater - Can be used as a chlorine-free supply of fresh drinking water (subject to regular maintenance of gutters; otherwise there can be health issues).
• Greywater - If purified, it can be used to flush toilets, water gardens and even to wash clothes.
• Blackwater - Toilet water: blackwater requires biological or chemical treatment and disinfection before re-use. Generally best to pass it on to sewerage farm.

For example, a water system could be designed to capture all available rainwater and use it for drinking, washing and watering the veggies. Water leaving the bathroom could be used to flush toilets and water other parts of the garden. In this model, mains water would provide a back up for the rainwater supply when there is scarce rainfall.

According to the Australian Greenhouse Office, such a model could reduce most household's consumption of mains water by approximately 80%.

3. Energy efficiency, capture and use - Most houses in Australia have sufficient raw energy - in the form of sunlight hitting them daily - to supply all the energy needs of the house and its inhabitants.

The need to heat, cool and light our houses can be all but eliminated through the deft application of passive design principles.

The need to heat water and power household appliances can then be met with solar hot water and grid-connected Solar Photovoltaic systems. This harnesses the sun currently hitting your roof to power water heating and electricity generation.

If we look at the make-up of energy use in the average Australian home we can see where and how a renovation may reduce or eliminate these outlays (and their associated greenhouse gas emissions).

• Space heating/cooling (39%) - Good design can eliminate the need to heat or cool our homes except in the most extreme weather.
• Lighting (5%) - By looking at how we use our living space, we can design it to be lit with natural light during the day.
• Electrical appliances (12%); standby energy use (4%); refrigeration (9%); cooking (4%) - Purchasing efficient appliances and fixtures should bring savings on both energy and water daily (See 'Install Efficient Appliances and Fixtures'.)
• Water heating (27%) - including the installation of a solar hot water system in your renovation would cut your energy requirements by over 80% (See 'Install Solar Hot Water' in 'Related Actions').

It can be seen from these figures that less than 50% of household energy needs would have to be met through the installation of a photovoltaic system (See 'Generate your own Electricity' in 'Related Actions').

4. Materials selection, use and re-use - Understanding the lifecycle of the materials we use and their potential impact on our health and the environment enables us to select products that are better for us and the planet.

Select building materials with the least environmental impact - The following list provides a common-sense guide to choosing your materials with the environment in mind:

1. Re-use existing materials from any demolition (this also minimises waste).
2. Use recycled materials and those with minimal environmental impact.
3. Use renewable resources (for instance, wood from sustainably managed forests).
4. Design for an extended lifespan (aim for over 100 years).
5. Design and build for de-construction, re-use, adaptation, modification and recycling.
6. Minimise the distance materials travel and select materials that assist passive-design heating and cooling of the house

Avoid building materials that leak toxic chemicals - Paints, composite wood, glues, carpets and many other building products can contain high levels of toxic chemicals (formaldehyde, benzene, trichloroethylene, etc). These chemicals are released slowly and contribute to 'Sick Building Syndrome', which causes symptoms ranging from allergies, headaches and fatigue through to nervous-system disorders, cancer and death. Seek equivalent products that don't contain these chemicals.

5. Minimise construction waste - With up to 40% of all waste coming from building sites, it will save the environment (and your dollars) to minimise the waste coming from your renovation in some of the following ways:

• Re-use existing building materials in the construction.
• Recycle material that you cannot use. Ensure your builders separate and recycle all waste coming from the renovation including masonry, concrete, wood and metals.

See Recycle Building and Construction Waste in 'Related Actions' for more information on recycling and recycled building materials.

Why this action is important

When we build or renovate our homes we determine the consumption pattern of that structure for the many decades of its life. It's a unique opportunity to make structural improvements to the efficiency of our homes and reduce their ongoing drain on the environment. Investing time, energy and money at this stage will give environmental and financial rewards for years in terms of reduced energy and water use and increased health and wellbeing.