
The Extra Cost of Energy
How much extra are Aussies paying on their energy bills to support live-at-home adult kids or extra housemates?
With high rent, unaffordable housing, and the rising cost of living, a recent report revealed that 72% of 19-year-olds are still living with their parents. More adults are choosing to stay at home longer or opt for co-living arrangements with friends or housemates. While living with others can help younger adults save on rent, it can also increase energy bills for parents or live-in landlords.
The energy comparison service, iSelect, combined appliance energy use data, usage habits of Australians aged 18 to 29, and state electricity prices to uncover the cost of energy when living with an additional adult. The study examined low, medium, and high usage profiles to capture different behaviours and the associated costs, ranging from light users who rarely switch things on, to heavy users who rely on multiple devices, take long showers and use appliances more frequently.
Estimated annual energy costs by usage level
Even a low-usage young adult uses around 1,800 kWh per year, costing households approximately an extra $436 annually. At moderate usage, this rises to almost 3,000 kWh per year, which equates to around $698 in extra energy costs. A high-usage young adult can add 4,648 kWh per year, costing parents or live-in landlords around $1,061 annually. The increase is steep, with costs over doubling from low to high usage, showing how lifestyle habits like streaming, gaming, and long showers can quickly drive-up bills.
The data shows how frequently 18–29-year-olds living at home use different devices and appliances, as well as the energy costs involved. The essentials, such as showers, lights, and kettles, are universally used, forming the baseline energy demand for every household with an adult child. Alone, these essentials can cost parents or live-in landlords roughly $559.42 annually at high usage.
Electronics, while widely used, have a low additional cost; on average laptops, headphones, and smartphones, cost less than $7 per year each. While gaming devices, used by roughly half of young adults living at home (stationary consoles 48%, gaming PCs 52%), are very energy-intensive; they can cost bill payers up to $85 per year at high usage, depending on the console.
Household appliances are widely adopted, with washing machines (83%), microwaves (77%), and vacuum cleaners (75%) representing significant contributors to household energy costs. Discretionary items like clothes dryers (49%), and air fryers (55%) aren’t found in every home. However, when used, their high energy use can cost an average of $18.56 for use of a dryer and $56.51 for an air fryer annually per device.
South Australia stands out with the highest average electricity rate at $0.44 per kWh. Parents or live-in landlords in the state face the most significant annual hit of approximately $1,463 for a high-usage adult and an average of $1,008 across usage levels. In contrast, Victoria is the cheapest state, with rates of just $0.26 per kWh. Households there pay around $586 on average for an extra adult, which is about $423 less than those in South Australia.
Across the eastern seaboard, costs sit around the national average. New South Wales ($747), Queensland ($754), and the ACT ($679) all show consistent pricing for parents with young adults at home. Western Australia and the Northern Territory sit slightly below this, averaging $739 and $689 respectively, while Tasmania households pay the second lowest at around $650 per year on average.

“With many young adults living at home longer due to rising living costs or moving in with friends in house shares, it’s important for households to understand the full impact on their energy bills. Everyday habits, such as taking a long shower or using a tumble dryer, can add up to hundreds of dollars a year.
“By being aware of these costs, parents and housemates can make small changes that add up, helping everyone save on energy without compromising their lifestyle. At iSelect, we help Australians compare energy plans from a range of providers to help find one that is best suited to their lifestyle and budget.”
Julia Paszka
General Manager – Utilities at iSelect
Written by:
Sarah Grealy
Digital Public Relations Specialist
0413 363 690
Sarah is our Digital Public Relations Specialist, and brings more than a decade of experience in the insurance comparison industry to iSelect.
With a passion for storytelling through data-driven insights, Sarah strives to empower Aussies with practical guides and tips.
About the data
The Extra Cost of Energy campaign estimates the full household energy costs that young adults (aged 18–29) contribute while living at home. Our analysis combines product-level energy consumption data, average household usage patterns, and state-based electricity pricing to build a clear picture of how lifestyle and location influence energy bills.
Data sources:
– 19 year old’s were living with their parents and this had increased to 72% in 2021 – Young people living with parents | Australian Institute of Family Studie–
Household appliances: Appliance energy consumption data was drawn from the Energy Rating Calculator. For each appliance, the top three brands with the highest energy ratings were reviewed, and the most popular 2–3 products were selected.
– Electronic and gaming devices: Energy usage estimates were collated from multiple publicly available sources (e.g., manufacturer specifications, independent testing reports). These values were averaged across common product models.
– Essential household activities: Estimates for daily essentials like showers, lighting, and kitchen appliances were derived from existing averages for the target demographic, based on both water/energy physics (e.g., heating water) and reported usage patterns.
– Product adoption and usage rates: Data on the proportion of Australians aged 18–29 living at home who use each device or appliance was sourced from Statista. This dataset informed the weighting of each product’s impact in the model — ensuring the results reflect real-world usage among young adults living with their parents.
– The Statista data was incorporated alongside appliance-level consumption figures, forming the baseline for calculating how common each energy behaviour is across Australia.
Usage assumptions:
– Shower consumption: A typical 6–8 minute shower was assumed to use around 80 litres of water, with energy requirements calculated at ~2 kWh per shower once heating and inefficiencies are factored in. This aligns with reported averages in Australia.
– Device usage rates: Product adoption rates (e.g. % of young adults using laptops, gaming consoles, air fryers, etc.) were sourced from national-level survey data of 18–29-year-olds living with their parents. These proportions were then applied consistently across all states.
– Low, medium, and high usage tiers: To capture behavioural differences, three usage profiles were created. Each profile scales consumption by frequency and duration of use.
– Low usage: Minimal daily usage of devices, shorter shower times, and limited appliance operation.
– Mid usage: Average frequency of use reflecting a “typical” young adult.
– High usage: Heavy reliance on multiple devices, longer showers, and more frequent appliance cycles.
– Weighting by adoption rates: Statista data provided percentage adoption figures for each product among 18–29-year-olds living at home. These proportions were applied across states when calculating average household impact — for example, only 49% of respondents reported using a clothes dryer, so the cost of that appliance was weighted accordingly.
Cost Calculations:
– State electricity rates: Per-kWh costs were sourced from state averages, ensuring that the regional price differences are reflected in total household cost estimates. South Australia, for example, carries a higher cost burden due to its higher average rate per kWh, compared with Victoria, which sits at the lower end.
– Annual consumption: Each product’s estimated kWh/year was multiplied by its relevant state rate. Household totals were then aggregated by category (Essentials, Household Appliances, Electronic Devices, and Gaming Devices).
Australian average: A national benchmark was calculated to compare state deviations from the average cost.
– Integration with Statista data: Weighted cost estimates were produced by multiplying each product’s annual energy cost by its adoption rate from the Statista dataset. This created more realistic averages that reflect the typical household composition of young Australians living at home, rather than assuming every home uses every device.
Key considerations
– While appliance adoption proportions were based on national survey data, they were applied uniformly across states due to the absence of state-level breakdowns.
– Estimates are intended to highlight broad trends and relative comparisons between states and usage levels rather than provide precise household bills.
– Actual household energy bills will vary depending on factors such as family size, building insulation, and individual behaviour.
– Appliance adoption proportions were based on Statista’s national survey data of 18–29-year-olds living with their parents. Although state-level breakdowns weren’t available, these national proportions were applied consistently across states to maintain comparability. Data available on request.
iSelect does not compare all energy insurance providers or policies in the market. The availability of policies will change from time to time. Not all policies available from its providers are compared by iSelect and due to commercial arrangements, your stated needs and circumstances, not all policies compared by iSelect are available to all customers. Some policies and special offers are available only from iSelect’s contact centre or website. Click here to view iSelect’s range of providers.
About 
At iSelect, we’re passionate about making Aussies’ lives easier by saving them time, effort and money. We are Australia’s go-to destination for comparison across insurance, utilities and personal finance products made available from our range of providers. Our service is provided at no cost to the customer.
iSelect General Pty Ltd (ABN 90 131 798 126. AFSL 334115) has partnered with Compare the Market (ABN 83 117 323 378. AFSL 422926) to compare a range of car insurers and policies. Not all providers in the market or all policies offered by the partners are compared and not all policies or special offers are available to all customers.
A number of our participating general insurance brands are arranged by Auto & General Services Pty Ltd ACN 003 617 909 on behalf of Auto & General Insurance Company Limited 111 586 353, both of which are related entities of iSelect Limited. Our relationship with those companies does not impact the integrity of our comparison service. Click here to view iSelect’s range of providers.
Any advice provided by iSelect is of a general nature and does not take into account your objectives, financial situation or needs. You need to consider the appropriateness of any information or general advice iSelect gives you, having regard to your personal situation, before acting on iSelect’s advice or purchasing any policy. You should consider iSelect’s Financial Services Guide which provides information about our services and your rights as a client of iSelect. iSelect receives commission for each policy sold that is a percentage of the premium or a flat fee. Ask us for more details before we provide you with any services.