In Australia, where water conservation is a genuine concern and energy prices continue to rise, running your household efficiently has never been more important. The good news is that your dishwasher, when used correctly, is actually one of the most water-efficient ways to clean dishes. Modern dishwashers use as little as 9-12 litres per cycle, compared to the 40-60 litres typically consumed when washing the same dishes by hand. However, there's still plenty of room to optimise your dishwasher's efficiency and reduce both your environmental impact and utility bills.
Key Takeaway
A dishwasher running a full load on an eco cycle uses significantly less water and energy than hand washing. By optimising your loading habits and choosing the right programs, you can save hundreds of dollars annually on utility costs while reducing your environmental footprint.
Understanding Your Dishwasher's Energy and Water Ratings
Every dishwasher sold in Australia displays an Energy Rating Label, which provides crucial information about its efficiency. The label shows both energy consumption (measured in kilowatt-hours) and water consumption (in litres per wash) based on standardised testing. Understanding these ratings helps you make informed decisions about both purchasing and usage.
Energy Star Ratings
The energy star rating ranges from 1 to 6 stars, with more stars indicating greater efficiency. A difference of one star typically represents about 27% less energy consumption. When choosing a new dishwasher, investing in a higher-rated model often pays for itself through lower running costs within a few years. A 4-star rated dishwasher might cost $50-100 more than a 3-star model but can save $30-40 annually on electricity.
Water Efficiency Labels
The WELS (Water Efficiency Labelling and Standards) rating similarly uses a star system. Dishwashers typically rate between 3 and 6 stars. The actual water consumption per cycle is listed in litres, allowing you to calculate annual water usage based on how often you run the machine.
Calculate Your Savings
To estimate annual water costs, multiply the litres per cycle by your typical weekly cycles, then by 52. Compare this to your water utility rate. Many 5-star dishwashers use under 11 litres per cycle, while older or budget models may use 15+ litres.
Always Run Full Loads
This is the single most impactful habit for improving efficiency. Running your dishwasher uses roughly the same amount of water and energy whether it's half-full or completely loaded. By waiting until you have a full load, you effectively halve your per-dish water and energy consumption.
A standard 14-place setting dishwasher can handle the dishes from a family of four for an entire day. Rather than running the dishwasher after each meal, collect dishes throughout the day and run a single cycle in the evening or overnight. If you find yourself running half loads regularly, consider whether a smaller capacity dishwasher or a drawer-style model might better suit your household.
Optimising Your Load
While running full loads is important, overloading prevents proper cleaning and often results in needing to rewash items, negating any efficiency gains. Learn your dishwasher's capacity by consulting the user manual, and ensure water can circulate freely around all items. Position items so they don't block the spray arms or nest together.
Use the Eco or Economy Cycle
Most modern dishwashers feature an eco or economy cycle specifically designed to minimise water and energy use. These programs typically run longer than normal cycles but use lower water temperatures and reduced water volume. The extended time allows dishes to soak and detergent to work more effectively without the energy cost of extremely hot water.
When Eco Mode Works Best
Eco cycles are ideal for everyday loads with typical soiling. They're perfect for dinner plates, glasses, and lightly soiled cookware. For best results, ensure dishes are scraped (but not rinsed) and properly loaded. Most eco cycles run for 2-3 hours but use 20-40% less energy than standard cycles.
When to Choose Other Cycles
Reserve intensive or heavy cycles for genuinely heavily soiled items like baked-on casserole dishes. Using intensive mode for normal loads wastes significant energy. Quick wash cycles use the most water per minute but are efficient for small, lightly soiled loads that must be washed immediately.
Myth Busted: Pre-Rinsing
Pre-rinsing dishes under the tap before loading them into the dishwasher can waste over 20 litres of water per load. Modern dishwashers and detergents are designed to handle food residue. Simply scrape solid waste into the bin and load dishes directly.
Optimise Water Heating
Heating water accounts for a significant portion of dishwasher energy consumption. Several strategies can reduce this cost without compromising cleaning performance.
Check Your Hot Water System
If your dishwasher connects to a hot water supply (some modern models heat water internally), ensure your hot water system is set to an appropriate temperature. For dishwashing, water entering the machine should be at least 50°C. Setting your hot water system higher than 60°C for dishwashing purposes wastes energy.
Run Hot Water Before Starting
Run the hot tap at your kitchen sink briefly before starting the dishwasher. This ensures the first fill is with hot water rather than the cold water sitting in pipes. This simple habit can improve cleaning effectiveness and reduce the energy your dishwasher needs to heat the water.
Consider Solar Hot Water
If your home has solar hot water, timing your dishwasher to run when solar-heated water is most available can significantly reduce energy costs. In Australian summers, solar hot water systems often heat water to temperatures well above minimum requirements by mid-afternoon.
Use the Delay Start Feature
Most dishwashers include a delay start function that allows you to schedule cycles for later. This feature offers several efficiency benefits:
- Off-peak electricity: Running your dishwasher during off-peak hours (typically late evening to early morning) can significantly reduce electricity costs if you're on a time-of-use tariff
- Solar energy: Households with solar panels can schedule cycles during peak generation hours to use free electricity
- Full loads: Setting a delayed start for the evening allows you to accumulate dishes throughout the day
Australian Electricity Tariffs
Many Australian households are on time-of-use tariffs where electricity costs significantly less during off-peak periods. Check your electricity bill or contact your provider to understand your tariff structure and identify the cheapest times to run appliances.
Maintain Your Dishwasher for Efficiency
A well-maintained dishwasher operates more efficiently than one that's neglected. Simple regular maintenance ensures your machine uses resources optimally.
Clean the Filter Regularly
A clogged filter forces the dishwasher to work harder and can result in poor cleaning that necessitates rewashing. Clean the filter monthly or more frequently if you notice food particles on clean dishes.
Check Spray Arm Holes
Blocked spray arm holes reduce cleaning effectiveness and can lead to running additional cycles. Regularly inspect and clear any blockages with a toothpick.
Descale in Hard Water Areas
Limescale buildup reduces heating element efficiency. In hard water areas, run a dishwasher cleaner or empty cycle with white vinegar monthly to prevent scale accumulation.
Smart Drying Strategies
The drying cycle consumes considerable energy. Reducing or eliminating heated drying can significantly cut energy use.
Air Dry Your Dishes
Many dishwashers allow you to skip the heated drying cycle. Simply open the door at the end of the wash cycle and let dishes air dry. The residual heat from the wash combined with air circulation dries dishes surprisingly quickly. This single change can reduce your dishwasher's energy consumption by up to 15%.
Use Rinse Aid
Rinse aid isn't just about spot-free glasses; it helps water sheet off dishes more effectively, resulting in faster drying with less energy. This is particularly important if you air dry dishes, as it prevents water spots without requiring heat.
Consider Your Detergent
Modern concentrated detergents are formulated to work effectively at lower temperatures and with less water. Using too much detergent doesn't improve cleaning but can leave residue that requires additional rinsing or rewashing.
- Use the detergent dispenser rather than placing tablets in the cutlery basket
- Follow package directions for your water hardness level
- In soft water areas, you may need less detergent than recommended
- Store detergent in a cool, dry place to maintain effectiveness
Long-Term Efficiency: Choosing a New Dishwasher
If your dishwasher is over 10 years old, replacing it with a modern efficient model likely saves money even if the old one still works. Older dishwashers typically use 15-20 litres per cycle compared to 9-12 litres for current efficient models. Similarly, energy consumption has decreased dramatically.
When purchasing, look beyond the purchase price to consider the total cost of ownership, including energy and water costs over the expected 10-15 year lifespan. Premium efficient models often provide the best value when lifetime costs are considered.
By implementing these strategies, you can reduce your dishwasher's environmental impact by 30-50% while saving hundreds of dollars annually on utility bills. In a country where water scarcity is a genuine concern, these habits contribute to both personal savings and broader environmental sustainability.