Energy Efficient Homes
An energy efficient home is one that has been designed using energy efficient principles. These homes rely less on artifical heating, cooling and lighting, and instead cleverly utilising natural means to maintain a comfortable and livable indoor environment, all year round.
By passively controlling the suns natural heat and light, and the prevailing cooling winds we can decide, through the design of the home, when and where we allow it enter the building and conversely keep it out.
Through a passive home design, we can control solar radiation, harnessing its warmth during the winter months while protecting the building from the hot summer sun.
In summer we limit the suns radiation entering the building by correct orientation and through the use of insulation, window location, size & type, and shading devices. We include windows to capture the prevailing breezes for cross vetilation, introducing
In winter, where the sun's position in the sky is lower, the same design will allow the sun to heat the home and the heat is retained through the very insulation used to keep the heat out in summer. Windows which allowed cooling winds in summer are shut to keep the heat in.
With the increasing costs of coal fired electricity the need to minimise and cut down on power consumption is becoming ever more important.
Energy Efficient Principles
Orientation |
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A home should be oriented and located on a block to maximise the amount of sunlight it receives. |
Floor plan layout |
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Daytime areas (those which we spend most of our waking hours in) such as the living room, should face north to maximise heat gain and lighting. Conversly rooms such as laundries and bathrooms should orient south, as these are not occupied for long periods of time |
Insulation |
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Wall, roof, ceiling and floor insulation, when specified and installed correctly ensures that the internal environment is sufficiently protected from external conditions. Insulation has a two pronged effect, it protects heat from entering the building during summer, whilst keeping the heat from escaping during winter. |
Glazing |
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Windows glazing in a typical home accounts for the largest amount of heat gain or loss. It is therefore important to treat these areas of the home. There is a large array of glazing systems from low e glass to double glazed argon filled window systems, which can significantly improve the efficiency of your home.
Other factors such as the size and location of glazing should be considered
in the design phase . |
Shading |
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Shading devices are critical for keeping a home cool in summer and preventing excessive heating of the home.
Shading can occur over windows and walls. Wall shading usually is in the form of covered verandahs or wrap around porches.
Window shading is best used externally. This protects windows from direct solar radiation.
Internal shading, such as vertical blinds, are not as effective as they dont stop solar radiation entering the building merely by the fact that they are located inside. |
Thermal Mass |
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Thermal Mass refers to a building material's ability to store heat when exposed to a heat source such as the sun. A building material which has a high thermal mass is advantages in winter because it is able to store large amounts of heat and retain this heat for a long period of time even after the sun has gone down. The heat is absorbed during the day and released into the room at night. Masonry bricks and concrete are good example of such materials |
Ventilation & Draughts |
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Ventilation encourages air movement within the home. It is escpecially beneficial during summer evenings after a hot day. Cross ventilation allows air to flow from one end of the building to the other through openings. Positioning of windows to coincide with natural prevailing breezes, optimizes the effects of cross ventilation.
Equally as important, draughts and air leaks in the building can drastically effect the homes ability to keep warm and can account for a large percentage of heat loss. Older original homes are notorious for this and can suffer from draught intrusion throughout the home. Usually location for draughts and air leaks are poorly sealed windows and doors, gaps in timber floors and skirting, open fire places with chimneys and service penetrations in walls. |
Landscaping |
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Soft landscaping around the home can have a indirect cooling effect.
Planting deciduous trees provides shading in summer and allows sun to penetrate into the building during winter when the leaves have all dropped off. |
Achieving An Energy Efficient Design
There is NO one standard design solution that can be implemented on all homes to achieve optimum energy efficiency. A home located in a hot and dry climate like Cairns requires a completely different set of design solutions and specifications than a home located in a cool climate such as hobart. Other variables such as trees around the site and overshadowing from adjacent property are factor which also require considertion and can have considerable effect on the what is specified.
It is the correct application of the principles discussed above, taylored specifically for the particular site, location and climatic conditions, that ensures the most efficient and effective design solution. This maximise its effectiveness of the design and eliminate over-specification. An example of over-specification is a home which has had a thicker and more expensive wall insulation specified, where a thinner and less expensive one would have been more appropriate, more cost effective and achieved the same results.
I personally tahe a holistic and practical approach, ensuring that I maintain a fine and controlled balance with the energy efficient principles and my client's requirements and budget.
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