Great for the environment & your pocket,
it make sense.
Now more than ever we must find more effective ways to construct our homes and buildings with greater energy efficiency. Energy consumption is significantly greater today than in past decades as lifestyle changes have resulted in increased use of energy resulting in disastrous environmental consequences.
Air infiltration from “wall leaks” is estimated to cause up to 39% of home energy loss. Concrete block walls are more airtight than timber frame walls and the thermal mass of block is one of the key elements of building a passive solar home. A house built out of block is more sound proof, structurally stronger and cheaper to build and run than most other forms of construction.
Passive Solar Design
Passive solar design is using natural energy from the sun to heat a building and the use of specific design principles to cool a building, which will reduce temperature fluctuations and make a home cheaper to run and more enjoyable to live in. Sadly the majority of buildings today are not designed to harness this free energy, possibly due to forces in the building industry with a vested interest in maintaining those designs.
However with clever designing you can have the benefits of passive solar design and still look like any other house at no extra cost. Strategically placed windows will allow the winter sun into the building to heat thermal mass (see below) while correct shading and ventilation will keep the building cool in the summer months. As building regulations develop and public awareness of sustainability issues increases, home buyers are demanding elements of a passive solar design.
The key elements of passive solar design.
1. Orientation
Orientation is the location and the direction in which the house faces. Correct orientation of the building coupled with a well designed plan can maximise the energy benefits of the environment.
2. Thermal Mass
Thermal mass materials such as block acts like a heat bank by storing the energy from the sun (and/or other heat sources) and radiating that energy back into the room as the temperature drops in the evening.
When compared to lightweight construction such as timber stud and plasterboard, high thermal mass materials exposed to sunlight in winter and shaded in summer can reduce total heating and cooling energy requirements by up to 50%.
Very thick thermal mass walls may take too long to heat, while those that are too thin won't store enough heat. In most cases, the correct thickness for a thermal mass material is about 100mm to 250mm.
Winter
In winter, thermal mass in the floors and walls absorbs radiant heat from the sun through the windows. During the night, the heat is gradually released back into the room as the air temperature drops. This maintains a comfortable temperature for some time, reducing the need for supplementary heating.
Summer
In summer, when the sun is high in the sky, the overhangs should shade the room completely keeping the thermal mass cool. Any heat inside the building is absorbed by the thermal mass which has a lower initial temperature than the surrounding air and acts as a heat sink. By absorbing heat from the atmosphere the internal air temperature is lowered resulting in improved comfort without the need for supplementary cooling.
3. Shading
Correctly sized overhangs such as eaves, verandas, pergolas and awnings are important in order to allow the low winter sun to fall on walls and in through windows but still large enough to shade the high summer sun from heating up the building. You can also position your home to get shade from neighbouring homes, terrain or trees when the sun is at its hottest, such as late afternoons in summer.
4. Insulation and R rating
While Insulation is an important part, it is only half of the energy efficiency story and in most locations, it alone cannot deliver the most energy efficient home. R-value only measures the reduction in heat transfer (to stop heat either entering or leaving a building) and for insulation it is the perfect metric because that is what insulation does. Thermal mass on the other hand, improves energy efficiency, because it absorbs and stores heat to delay it from entering or leaving a building.
So thermal mass construction, combined with sound passive solar design and good insulation is the ideal solution.
Why use blocks?
Note – 140mm internal blocks can be finished with gyprock, render, painted or simply left. They can also be ordered in special colours.
Building external walls with 190mm hollow block combined with insulated material such as foilboard attached to the inside (see Block Insulation) and 140mm hollow block for the internal walls not only saves you money on construction costs and energy bills, other benefits include:
· Better sound proofing – reduces unwanted outside noise keeping the interior of your house quiet and peaceful. If blocks are used for the internal walls this will also greatly reduce sound transfer between rooms.
· Structurally stronger – Blocks can be reinforced as much or as little as you want. Cores in the block can be filled with concrete and reinforcing bar to give you added strength if required. This is one of the reasons blocks are used in cyclone areas. (See also Bond Beams)
· Fire and termite resistant – Masonry, there’s nothing to burn or eat here.
· Speed of construction - Block walls can be constructed with surprising speed, the face area is equal to 4 bricks and the whole block is equal to 8 bricks. Quick & easy construction = Lower construction costs.
Finishes – Blocks come in a range of finishes, from a plain concrete block which may be rendered, bagged or just simply painted, to a smooth coloured block or a Colonial Sandstone Block that captures the old world charm of yesteryear.