A short newsletter giving practical advice on minimising your energy for heating and cooling focusing on low cost easily implemented ideas.
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What has colour inside the house to do with energy use?
New building regulations for home units and other multi-occupancy dwellings.
What can we do to minimise energy losses through our floors?
Using light rather than dark colours in a room saves air conditioning energy as well as the energy for the lights. The light coloured surfaces reflect the light instead of absorbing it. This means less light is needed to achieve the desired brightness in the room. Light colours also give a more even light which is easier on the eyes. Generally for energy efficiency the:
Before looking at the building regulations, a brief update on the Productivity Commission Inquiry on Energy Efficiency reported on last month. A number of submissions have been made on the draft report. My own submission is a 12 page technical paper. As it is largely an in depth justification of my claims made in the last newsletter, I won't repeat the details. The Commission will shortly be holding public hearings and then will finalise the report.
The main topic of this Editorial is the new energy efficiency standards for home units and other multi-occupancy dwellings which came into force on 1st of May 2005. These buildings were not subject to the previous energy efficiency requirements which only applied to traditional houses.
Given that purchasers of home units are not able to alter the design to improve energy efficiency, I think the changes are highly desirable. Furthermore, I believe in most states nearly all home units would have air conditioning. This means improving the home unit efficiencies will have a big impact on energy use and hopefully also on the peak electricity demand. (Limiting the growth in peak electricity demand will reduce projected future electricity price rises for all of us.)
The code addresses energy use in the following areas:
The requirement to maintain systems is an important innovation, as some types of complicated systems can be efficient initially but then deteriorate.
The approach allows for trade-offs between different areas, so a more efficient air conditioner can be traded off against less insulation or vice versa. This should help minimise the extra costs. As with most such changes I expect there will be some initial extra costs, but within 2-3 years the extra cost should drop significantly as builders work out the most cost effective ways to meet the requirements.
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The best way to minimise losses through floors depends on the type of floor and your climate. When replacing your floor coverings remember these recommendations. Before spending any money on extra insulation for floors, remember that the most important surfaces are windows and ceilings followed by walls and then finally floors. So don't spend extra on your floors above choosing the best floor covering for your house, until you have improved the other surfaces to the maximum economically feasible. (Although in most cases it is not feasible to increase wall insulation unless for example recladding a timber wall.)
Timber floors don't store heat, it pretty much passes straight through, so the insulation value of the floor is most critical (except perhaps in humid climates). For timber floors a thick carpet with a thick underlay can make a noticeable difference in heat loss through the floor. Ideally the floor should be insulated underneath if there is an accessible crawl space. However, if the insulation is exposed to the wind the insulation should be foil faced (foil down) to stop the wind blowing through the insulation. Suspended concrete floors should generally also have carpets, but extra insulation underneath is not generally recommended except in very cold locations.
Concrete slab on ground floors actually store heat. If the winter sun shines directly on the floor in the temperate and cold parts of Australia, the best floor covering is no covering. Ceramic tiles, slate (and to a lesser extent lino) all qualify and should be as dark as feasible to absorb the sunlight. The concrete will then release the heat during the evening and night. In other rooms or where the sun doesn't shine on the floor it is less critical, however you are still better off with no covering or a thin covering. Many people feel that this recommendation must be wrong because if you tread onto a concrete or tile floor in winter with bare feet the floor feels cold. The floor feels cold because the concrete is conducting the heat from your feet (which are at nearly body temperature) to the floor, even if the floor is actually above the room temperature. However by having the bare concrete or tile floor, the air temperature will generally be warmer than it would otherwise be. If you are stepping onto a carpet with bare feet the insulating properties of the carpet reduce the amount of heat conducted away, so your foot doesn't feel as cold. I recommend a small mat where you get out of bed and keep your slippers nearby, or have thin carpet in the bedrooms and exposed floors elsewhere.Back to Contents
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