During summer, Victoria's electricity market experiences high demand, primarily from the increased use of air-conditioning on very hot days (DPI 2010).
Since 1994, the most popular system of cooling in Australia has increasingly been reverse cycle/heat pump air conditioning (61% in 2008, up from 50% in 1994). In Victoria, and similarly across the nation, the proportion of households with an air conditioner in use has almost doubled from 1994 to 2008 (ABS 2008).
Around two-thirds of Victorian households (67%) had one or more air conditioners used for cooling. Melbourne and regional Victoria had similar rates at 66% and 70% respectively. The SRs of Inner Melbourne, (which includes the CBD and inner city), and Barwon-Western District (including Geelong, Colac and the south-west of Victoria) had lower rates of households with one or more air conditioners compared to Victoria at 43% and 56% respectively. While Goulburn-Ovens-Murray SR (including the towns of Shepparton, Echuca and Wangaratta) had 91% of households with one or more air conditioners.
Couple households in Victoria, both with and without children, were more likely to have one or more air conditioners (75% and 74% respectively) than Victorians living alone (57%). In regional Victoria, lone parent families had a lower rate (57%) of one or more air conditioners in the household when compared to regional Victoria's overall rate.
In Melbourne, it was more likely a household with an income of $110,000 or more will have one or more air conditioners (77%) than a household with an income of less than $25,000 (54%). However, ownership of air conditioners in regional Victoria showed little change with differing incomes.
Victorian dwellings with insulation had a higher rate (75%) with one or more air conditioners than dwellings without insulation (44%).
Across Victoria, less than half (45%) of rented dwellings had one or more air conditioners compared to three-quarters (76%) of dwellings either owned outright or being purchased.
Of the 1,423,800 Victorian households with air conditioners (including households which did not use it for cooling), most used their air conditioner for cooling nine weeks or less during the 3 summer months. 15% of households with air conditioners used their air conditioner during all summer months.
In regional Victoria, 20% of the 413,400 households with air conditioning used it during all summer months, compared to Melbourne's 12% (of 1,010,400 households). A smaller proportion of Victorian households (6%) did not use their air conditioner for cooling at all during summer months.
One person households were more likely to use the air conditioning less during summer months. 44% of one person households used their air conditioner four weeks or less in the summer months compared to 30% of six or more person households who used it for the same amount of time.
For Victorian households with a household income of less than $25,000 per annum, 43% used their air conditioner four weeks or less during the summer. This was higher than the 35% of households with an income of $110,000 or more who used their air conditioner for four weeks or less.
The proportion of households with no air conditioner use during the summer months was greater for rented dwellings and also for dwellings that did not have, or did not know if they had insulation. For rented dwellings, 14% did not use air conditioning and for both dwellings without insulation or unsure if they had insulation, 12% did not use air conditioning. Both proportions were over twice the rate of total Victorian households who did not use air conditioning during the summer (5.5%).
Households with children in regional Victoria had a higher rate of air conditioner use with 29% using it for all 13 weeks of summer compared to 17% of households without children. Also in regional Victoria, households with no children showed a higher rate (25%) of use for five to nine weeks during summer than households with children (17%). This was not the case in Melbourne where households with and without children showed similar rates of air conditioner use (30% and 29% respectively).
ABS (Australian Bureau of Statistics) 2008, Environmental Issues: Energy Use and Conservation, Cat. no. 4602.0.55.001, ABS, Canberra.
DPI (Victorian Government Department of Primary Industries) 2010, Providing Sufficient Capacity, <http://www.new.dpi.vic.gov.au/energy/energy-policy/providing-sufficient-capacity> last viewed 5 May 2010.