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Building & renovating

Building or renovating, creating an energy efficient home will help reduce your electricity use in the long run. Here’s a list of tips that can improve the energy efficiency of your property.

Put the sun in the shade

Direct sun can generate the same heat as a single bar radiator over each square metre of a surface (ouch). Adding extra shading like eaves, pergolas and plantings can block up to 90% of this heat. 

Top tips outside the home

When creating a more energy efficient home, it can be what's outside that counts. 

  1. Minimise your bore use

    A bore uses electricity to pump water from the ground. Planting a water wise garden can help reduce your bore usage.

  2. Switch to solar power

    Generating your own clean electricity from the sun can help you use less energy from the grid. Find out if solar is right for you.

  3. Switch to solar hot water

    Heating and cooling can account for up to 18% of your energy bill. It takes a fair bit of energy to heat water, so it makes sense to get the sun to heat it for you.

  4. Get a pergola with louvers

    Pergola louvers should be angled at 34ºC with optimal spacing, which will let in the winter sun for warmth; and block out the summer sun to cool your house down.

  5. Switch to solar hot water

    Unshaded windows allow the summer sun to heat up the home and provides a quicker escape route for any heating generated indoors during winter. 

    Window awnings or roller shutters can be used to reduce the amount of summer sun that enters the home, but allow the lower winter sun to enter. Strategically placed shade sails can also be used for similar effect.

    All external window shading is enhanced by the use of internal blinds or curtains with fitted pelmets.

  6. Plant deciduous trees to control heat

    Deciduous trees planted on the side of the house that faces the sun will shade windows in summer and they’ll lose leaves in winter to let the sun in. Nature at its best!

    In winter, remember to leave curtains and blinds on windows facing the sun open, to allow the sun to enter and warm the home naturally.

  7. Minimise reflected heat

    Paving under windows that face the sun can increase the heat in a room, as the sun bounces off the paving and through the glass.

    If practical, replace the paving near windows by using waterwise ground covers, with mulched beds, moving the paving further away. 

    Outdoor mats can also be used to shade paving if necessary. 

Tips for more efficient heating and cooling

The angle of the sun changes dramatically from summer to winter. Well designed homes use this to their advantage to maximise the entry of the low winter sun and restrict the exposure to the high summer sun.

  1. Don't go too hot or cold with the temperature

    Your fridge temperature should be below 5°C and your freezer should be set between -15/-18°C. Just remember, for every degree colder, you can increase your running costs by 2–4%.*

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  2. Install insulation

    Insulation actually works; it keeps the heat out in summer and stops heat escaping in winter. 

    If you have a timber home you may also want to consider insulating the walls and even the floor if it is raised off the ground.
    Where possible, use a good quality, high rated insulation. Silver foil on both sides of the insulation gives maximum effect. 

    Extract vents in the roof will also help heat escape from the roof cavity. If your roof needs repainting, choosing a light colour can also help.

  3. Make your air conditioners job easier

    Close off internal doors to unused rooms and use light coloured blinds to prevent heat transfer through the glass.

  4. When the breeze is cool let it in

    After a hot day, cool your home by taking advantage of the cool evening breezes. Keep lower branches on trees and other vegetation trimmed to prevent them from blocking the breezes.

    Consider installing security screens, which will allow you to leave windows and doors open late into the evening. 

    Plus, keep curtains or blinds and internal doors open when practical, to allow cooling breezes to go right through the home. 

Building a new home

The angle of the sun changes dramatically from summer to winter. Well designed homes use this to their advantage to maximise the entry of the low winter sun and restrict the exposure to the high summer sun.

  1. When building choose a north facing block

    That means a block that is longest in an east-west direction as it maximises heating and cooling efficiencies.

    Ideally it should not be shaded by tall trees or buildings to the north so you can take full advantage the winter sun.

  2. Go large with the windows on the northern side

    North facing windows will give you the most natural light and will help warm your house in winter. 

    If possible, make your north wall about 1/3 to 1/2 glass. This way, winter sun will be able to enter and naturally warm your home but can easily be protected from summer sun by eaves, deciduous plants or pergolas.

    Go smaller on the south
    South facing windows get virtually no direct sun all year, but can cause
    major heat loss during winter. Don't make them too big – small enough to limit heat transfer in winter but big enough to allow cross-breezes in

    Go even smaller on the east and west
    In winter, east facing windows don’t receive enough sun to provide warmth yet they let valuable heat out. In summer, they can cause the house to heat quickly as they receive morning sun and are difficult to shade effectively.

    West receive full, hot afternoon sun and are very hard to shade. If needed for views, position them under a veranda or carport and apply vertical screens. 

    Trees on the west side should be tall varieties that will shade the home but still allow westerly breezes underneath.

  3. Use eaves to shade your home

    Having decent sized eaves will shade your windows and external walls, keeping your house cooler in summer.

  4. Plan where you plant

    Strategically placed trees and shrubs not only look great but can shade your home in summer and welcome the sun in to your home in winter when they drop their leaves.

    On the north side, use deciduous trees and avoid planting evergreen trees that will block winter sun.

    Trees and shrubs are great for minimising heat gain through east and west walls in the summer. Tall evergreen trees on the west side offer shade from the hot afternoon sun and still allow cool sea breezes to flow underneath.

    Brick paving under north facing windows reflect summer heat into the home. Place paving further away from the house and use water-wise groundcovers and small shrubs beneath the windows as a cooler option.

  5. Add more character with a verandah or pergola

    Adding a pergola with slats at the correct angle can let in the low winter sun while providing shade in summer.

    Removable shade cloth, or deciduous vines over a pergola, can achieve a similar effect. If space is a problem, vines grown on latticework are great too (and look good)!

  6. Position your living areas on the north side

    As much as possible, choose a plan that has your living areas facing north and your bedrooms facing south. 

    In winter, your living rooms catch maximum sun for warmth and light, while in the heat of summer your bedrooms are shielded from the sun for cooler sleeping conditions.

Seal up your home against air leaks

Air leakage can account for 15–25% of winter heat loss at home and is the main suspect in allowing the cool air generated by the air-con, to escape in summer.