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Environmental impact of household energy use
FINAL ENERGY CONSUMPTION IN THE RESIDENTIAL SECTOR(a)
TRENDS IN ENERGY USE
Between 1983–84 and 2003–04, energy use in the residential sector grew by 52% or an average of 2.2% per year. Increased household energy use is predominantly the result of population growth, and an associated increase in the number of dwellings needing energy for power and heating. It is also related to an increase in average use per person, influenced by the increasing size of dwellings and the decreasing number of people per dwelling (see Australian Social Trends 2003, Changes in Australian housing). Changes in population and in average energy use are expected to continue to increase residential energy consumption in the future. Between 2003–04 and 2029–30, energy in the residential sector is projected to increase at 1.7% a year to around 650 PJ.(EndNote 6)
(a) Projected consumption.
(b) Includes bagasse (EndNote 5) and woodwaste.
(c) Mainly coal and petroleum products.
Source: ABARE, Australian Energy, national and state projections to 2029–30, 2005; ABARE electronic datasets.
MAKING LIFE COMFORTABLE
Energy is essential for household comfort. However, the source of that energy is important in assessing greenhouse efficiency. Despite new homes becoming more energy efficient, Australians are using more energy per person in the home. This may be partly due to an increase in the number, type and use of electrical appliances in households. Some household items, such as dishwashers and airconditioners, which may have once been seen as luxuries, have become more common in Australian homes.
...WHITE GOODS AND ELECTRICAL APPLIANCES
White goods and electrical appliances account for 30% of total energy consumption and the greatest proportion of household greenhouse gas emissions (53%).(EndNote 9) Most white goods and household appliances use electricity. Consequently, the number, type, frequency of use and energy efficiency of white goods and appliances in the home impacts significantly on the energy consumed and emissions produced.
In 2005, almost every household owned at least one fridge, television and vacuum cleaner. The number of households with two or more fridges in use increased from 24% to 33% between 1994 and 2005. In 2005, 42% of households had a dishwasher, an increase from 25% in 1994. The proportion of households with computers increased from 45% in 1999 to 68% in 2005.
As white goods and other appliances account for most household greenhouse gas emissions, people's decisions about purchase and use of these items is important. The introduction of energy ratings and labelling has helped consumers in their decisions. However, the reason people buy certain brands and sizes of appliances usually relates to the initial capital cost of the item and the long term decrease in cost of energy bills, rather than the reduction in environmental cost.(EndNote 10)
(a) Includes lighting.
Source: Australian Greenhouse Office 2005, Your Home Technical Manual.
(b) Data for 1994 is June 1994. All other periods are March of that year.
(c) No data available for 1994.
Source: Environmental Issues: People's Views and Practices, March 2005 (ABS cat. no. 4602.0).
...WATER HEATING AND COOKING
Water heating accounts for 27% of household energy consumption, and is the second largest source of household greenhouse gas emissions (28%) after the use of white goods and appliances (53%) in the household sector. Solar energy is by far the cleanest source of energy for this purpose, with the capacity to provide up to 90% of a household's hot water requirements, depending on climatic conditions.(EndNote 7) In 2005, 51% of households used electricity for water heating. In the same year, gas was used in 39% of households and solar in less than 5% of households.
In 2005, over half (54%) of households used electricity for cooking and 39% used gas. Cooking uses a relatively small amount of energy (4% of total household energy consumption), producing less greenhouse gas emissions (6% of total) than most other energy uses in the home. Gas cooktops and ovens produce less than half the emissions than comparable electric units.(EndNote 7)
...HEATING AND COOLING SPACE
In 2005, the proportions of homes using gas and electricity for heating space were similar (33% and 32% respectively). While the proportion of homes using gas for heating has remained constant since 1999, electricity use increased from 28% in the same time period. The amount of pollution produced by heating a home is dependent on the energy source. Electric systems may produce up to six times more greenhouse emissions than an efficient gas central heating system.(EndNote 7)
The number of homes with airconditioners increased substantially between 1994 and 2005 from 33% to 60%. Most cooling systems and appliances use electricity, with the type of airconditioner being an important determinant of the amount of electricity needed to cool a home. At their best, in conditions of low humidity, evaporative cooling systems can use one-quarter of the electricity required by a refrigerated system; reducing both household energy costs and greenhouse gas emissions.(EndNote 12) In 2005, 57% of households had a reverse cycle/heat pump as their main cooler, 22% had an evaporative cooler and 19% had a full refrigerated system.
BUILDING ENERGY EFFICIENT HOMES
Energy used by households varies with climate and lifestyle. One important factor impacting on household energy use is home design and insulation. The material used in the construction of the outside walls of a dwelling greatly influences its thermal properties.For example, brick dwellings can be more energy efficient than fibrocement or timber dwellings in cool temperate environments because of the way brick responds to outside temperature changes.(EndNote 7)
In 2005, 71% of dwellings across Australia had their walls constructed with double brick or brick veneer, 13% from timber and 6% from fibrocement. Between 1999 and 2005, the proportion of brick dwellings increased from 68% to 71%, whereas the proportion of timber and fibrocement dwellings decreased from 15% to 13% for timber and from 8% to 6% for fibrocement.
Many new homes are now built to maximise the passive use of solar energy. For example, large windows on the north side of the house let the sunshine in during winter, but can be shaded from the summer sun.(EndNote 7) The effect of the orientation of a dwelling is often reflected in the household energy bill.
Adequately insulated ceilings, walls and even floors can greatly reduce energy consumption, and therefore greenhouse gas emissions. The number of dwellings with insulation increased from 52% in 1994 to 61% in 2005.
In 1999, the Ministerial Council on Greenhouse and the building sector agreed upon a comprehensive strategy to make Australia's buildings more energy efficient.(EndNote 13) Energy provisions were introduced into the Building Code of Australia to reduce greenhouse gas emissions. They aimed to reduce residential energy consumption and increase thermal comfort by encouraging improved building design. The strategy defined an acceptable minimum level of energy efficiency for new buildings and the House Energy Rating Scheme, which in many areas are a mandatory part of the development approval process.(EndNote 7, 13)
In a range of surveys and past research conducted as part of The National Greenhouse Strategy, the environment has emerged as an issue of concern for large numbers of Australians. However, although people agree more can be done to help protect the environment, evidence suggests that adoption of environmentally friendly behaviours is greatest where it is convenient and where it does not require large investments of time or money. Also, it is possible that people may become complacent, feeling that they are "doing their bit" if they recycle, use unleaded petrol and buy the occasional energy efficient appliance. This complacency may be a barrier to further modifications of behaviour.(EndNote 10)
Households were surveyed on their attitudes to environmental issues and concern every 2–3 years between 1992 and 2004. In 2004, of all Australians aged 18 years and over, 57% stated they were concerned about environmental problems. The level of concern had decreased considerably since 1992, when three-quarters (75%) of Australians stated they had environmental concerns. The greatest falls in concern were in the younger age groups, such as the 18–24 years group where concern fell from 79% in 1992 to 49% in 2004. Of the 57% of people concerned about environmental problems, only 13% formally registered concern (through writing a letter, telephoning, participating in demonstrations, signing a petition or by some other means) and 29% donated time or money to help protect the environment.
Energy conservation in the home sometimes requires significant changes in behaviour. People generally understand that there are personal financial benefits from conserving energy in the home, but these benefits are sometimes outweighed by a desire to maintain quality of life and to save money in the short term. First home buyers, for example, often do not have the resources to invest in more expensive, energy efficient appliances, insulation or quality window coverings. Second and third home-buyers, however, are usually in a better position to consider more options when selecting or replacing major appliances and for house design.(EndNote 10) In 2005, 43% of households said they considered cost to be the main factor when buying a new white good, 44% nominated the energy star rating as a main consideration, and only 11% of households stated an environmental factor as their main consideration. Many households with insulation said their main reason for installing it was to achieve comfort (83%), rather than to save on energy bills (10%) or use less energy (4%).
ENVIRONMENTAL CONCERN BY AGE(a)
2. Department of the Environment and Heritage, Australian Greenhouse Office 2006, National Greenhouse Gas Inventory 2004, AGO, Canberra.
3. International Energy Agency 2005, Key World Energy Statistics, 2005 edition, IEA, France.
4. Department of Environment and Heritage and the Australian Greenhouse Office 2005, Tracking to the Kyoto Target: Australia's Greenhouse Emissions Trends 1990 to 2008–2012 and 2020, DEH, Canberra.
5. State and Territory Greenhouse Gas Emissions – an overview, viewed 24 March 2006, <http://www.greenhouse.gov.au/inventory/stateinv/pubs/stateoverview.pdf>.
6. Akmal, M, Riwoe, D 2005, Australian Energy, national and state projections to 2029–30, Australian Bureau of Agricultural and Resource Economics, Canberra.
7. Australian Greenhouse Office 2005, Your Home Technical Manual, viewed 13 December 2005, <http://www.greenhouse.gov.au/technical/>.
8. Australian Bureau of Statistics 2005, Population Projections Australia Series B, 2004–2101, cat. no. 3222.0, ABS, Canberra.
9. Australian Greenhouse Office, History of the labelling program in Australia, viewed 19 December 2005, <http://www.energyrating.gov.au/history.html>.
10. The Department of Environment and Heritage and the Australian Greenhouse Office, NGS Communications Strategy: Review of past research 26/07/2000. viewed 19 December 2005, <http://www.greenhouse.gov.au/government/ngs/community-awareness/pubs/literature.pdf>.
11. Australian Bureau of Statistics 2001, Energy and Greenhouse Gas Emissions Accounts 1992–93 to 1997–98, cat. no. 4604.0, ABS, Canberra.
12. Government of South Australia, Take the Heat out of Home Cooling, viewed 19 December 2005, <http://www.sustainable.energy.sa.gov.au/
13. CSIRO Division of Building, Construction and Engineering for the Australian Greenhouse Office, 1999, Scoping Study of Minimum Energy Performance Requirements for Incorporation into the Building Code of Australia, viewed 21 February 2005, <http://www.greenhouse.gov.au/buildings/publications/s_study.html.>.