CHARACTERISTICS OF AUSTRALIAN HOMES AND IMPLICATIONS FOR ENERGY EFFICIENCY

The size and characteristics of Australian homes have implications for household energy use and greenhouse gas emissions. For example, the amount of floor space affects the amount of energy needed to heat or cool a dwelling.

Between 1994 and 2008, the number of homes with four or more bedrooms rose from 21% to 29%, while the number of one, two and three bedroom homes all decreased. Despite the increasing size of homes, household size in Australia is decreasing, from 2.6 people per household in 2001 to projections of between 2.2 and 2.3 people per household in 2026. This decline reflects a projected trend where increasing proportions of people will be living in lone person households and in couple families without children. This means that more space needs to be heated and cooled per person, requiring more energy.

The materials used to build homes influences energy consumption. High thermal mass materials such as brick and stone are more energy efficient than fibro cement and timber, as they take longer to respond to temperature changes. The use of timber, fibro cement and double brick decreased between 1999 and 2008.




Home insulation – that is insulation in ceilings, walls and floors – improves energy efficiency for heating and cooling. The proportion of insulated dwellings in Australia was 62% in 2008, up from just over half (52%) in 1994. In 2008, nearly one-fifth (19%) of households did not know if their dwelling had insulation, up from 15% in 1994.




Most of the winter heat loss and summer heat gain of dwellings occurs from the roof or ceiling. Roof and ceiling insulation can save up to 45% on energy consumption for heating and cooling (DEWHA 2008). Of those dwellings with insulation, 98% insulated the roof or ceiling. The most common type of insulation installed in the roof or ceiling was fibreglass, wool or polyester batts (55%) followed by sisalation or reflective foil (22%).

Comfort was the main reason why nearly all (83%) householders had installed insulation in their homes. Only 4% of households said they had installed insulation to reduce energy use and 11% said it was to save on energy bills. Of those households with no insulation, the most common reason for not having insulation was that they were not the home owners or were not responsible (34%). This was followed by cost (17%) and that they had not considered installing insulation (12%).

	Owned outright	Being purchased	Rented	Other	Don’t know	Total
	%	%	%	%	%	%
Window coverings designed to stop heat or cold (a)	54.0	51.1	33.2	45.0	57.2	47.1
Outside awnings or shutters	41.0	30.3	19.5	36.1	47.2	31.6
Tinted glass or solar guarding	11.9	12.1	4.2	6.7	9.7	9.7
Double glazing	2.8	3.5	1.5	0	9.7	2.6
Louvre windows	4.7	4.7	4.4	3.2	0	4.6
None of the above	24.6	30.1	53.6	35.2	30.2	34.6
(a) Includes boxed pelmets that are designed to stop heat loss or gain. Source: ABS, Energy Use and Conservation survey, March 2008. Unpublished data available on request.

Window protection and shading reduces the amount of heat lost or gained by a dwelling. As windows can be the source of up to 40–60% of heat loss from a house, appropriate window treatments can improve household energy efficiency and reduce heating and cooling costs (SEDO 2008). In March 2008, more than one-third (35%) of all households did not have any type of window treatments to reduce heat loss or gain. This proportion was even higher for rented homes, where over half (54%) had no window treatments to reduce heat loss or gain.