The building of a house is likely to be one the largest investments in your lifetime. Some simple planning right at the beginning can make a big difference to how much energy your house will use into the future. 

Getting the design right from the beginning and incorporating passive solar design principles will make a huge difference to the amount of energy it will take to heat or cool your home. For cooler climates like Melbourne’s this means placing the living areas on the north side of the house so that large windows will let the sun in and warm the house in the winter. Removable shading or eaves can be used to keep the sun out in summer when it is higher in the sky, but will let it in during winter when it is at a lower angle. Do not put permanently shaded areas, such as an alfresco on the north side.

If you’re choosing a block of land for your house, keep this in mind. North should be on the longer edge of the block to allow the best solar access for the living areas. This will also mean that plenty of natural light will make your house pleasant to live in and reduce the need for artificial lighting. Avoid long blocks that run north south, especially if north is at the front. 

Thermal mass is also important as this helps to moderate the temperature inside the house. This could be in the form of a concrete slab floor or stone or brick walls in areas where the winter sun can shine on them. In winter the warmth from the sun is stored in the thermal mass and released into the house as the temperature inside the house cools. In summer it works in the opposite way by absorbing the warmer air inside the house keeping the house cool.

Another important consideration in the design is cross flow ventilation. This is achieved by creating large opening windows or doors which you can open up to allow the cool southerly breezes to pass through the house.

Once you’ve got the design right, the next important consideration is to add the appropriate amounts of insulation to the ceiling, walls and raised timber floors. It is important that there are no gaps in the insulation and that it is cut to fill gaps and not squeezed into place. Even small areas missed can reduce its effectiveness by 50 per cent. Good insulation also means sealing all gaps and spaces, especially around windows and doors and above ceiling fans.

It is then time to focus on the electrical appliances in the house. Always go for the most efficient Star Rating, even if they cost more upfront. The extra upfront cost may be quickly recouped over the life of the product. For example, using an LED downlight instead of a halogen downlight uses approximately 80 per cent less power. So even though it may cost six times more, the extra cost is recouped in the first year and then the energy savings are free for the next ten years.

Despite the change to feed in tariffs, in recent years the same can be said of solar panels. Developments in the technology are changing rapidly, as are the prices. The correct size of a system will depend on individual households, but typically a 2.5 kW system will cut household carbon dioxide emissions by 30 to 50 per cent and produce about 10kW hours of power per day, on average over a year. Some rough calculations show a payback on the system of about four to five years.

Building energy efficient homes also results in the construction of better homes. These homes are more comfortable to live in, filled with natural light and healthier for you and your family.


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