Frequently Asked Questions – Appliances

What are the advantages of a front loading type of clothes washer? Front loading machines usually use less energy and water (but not always). There are a number of issues to consider when choosing a type of washer. The Living Greener website has more information.
Why do some clothes washers with a better star rating use more electricity? The Energy Ratings take into account the capacity (load size) and the spinning performance of the clothes washer (i.e. how much moisture is left in clothes after spinning). A larger machine will use more energy but it will appear more ’efficient‘ (less energy per kg clothes washed for a full load). A model that has a better spin performance may get a marginally higher star rating than a model of the same capacity and energy consumption but with a poor spin performance. Spinning performance is taken into account for washer star ratings because it is assumed some consumers will use a clothes dryer to dry their clothes. A good spin performance in a clothes washer will reduce the energy consumed by a clothes dryer and will also reduce air drying time on the clothes line.
Why do some clothes washer with a better star rating cost more to run? Some clothes washers import hot water from the tap and other machines heat the water internally. Cold-only connection with an internal heater is most common for European front loading machines although many are available with dual (hot and cold connections). It is often cheaper to import water from a hot water system as many households have access to cheap hot water rates through gas, solar or off-peak electric hot water systems. Consequently, although both types may use a similar amount of energy, the machine that imports hot water will be cheaper to run if the household has access to cheaper hot water. The energy rating label considers energy related aspects – it is not a cost rating scheme. Costs are especially complicated for clothes washers because they vary greatly from house to house. They are given as an indication only.It is important to carefully check out whether the machine you intend to purchase has a single connection (cold only with an internal heater) or whether it has a dual connection (hot and cold).
I have solar hot water. How should I choose a dishwasher or clothes washer? In the interactive appliance product listing for dishwashers it is assumed that all water is heated as required within the dishwasher using electricity, as most dishwashers have only a single cold-water connection. Solar hot water will not affect dishwasher electricity costs for a dishwasher with a cold-water connection only (also see next question on supplementary hot water energy for dishwashers).For clothes washers, most top-loading models have both hot and cold connections but only some front loaders have hot and cold connections. Washers with a cold-only connection and an internal heater are common for European front-loading machines. Solar hot water will not affect clothes washer electricity costs for a clothes washer with a cold-water connection only as all water is heated internally. So, look for a dual water connection machine if you are considering a front-loader and you want to utilise your solar water heater or less expensive or low greenhouse gas-emitting hot water supply, such as gas.
What is the supplementary energy consumption for dishwashers? The energy rating label shows the total energy consumed by the dishwasher when measured to AS/NZS2007.1 for an assumed usage of 7 days per week. Virtually all dishwashers on the market now have a single plumbing connection and this can usually be connected to either a cold water supply (called the primary connection mode) or to a hot water supply (called the supplementary water connection mode). Almost no dishwashers are now available with dual water connections (both hot and cold inlets).In the case of a cold connection, the dishwasher draws in cold water and heats the water internally (using electricity) as required throughout the program. Typically a dishwasher will have between 3 and 5 separate fills during a program and usually 2 or sometimes 3 of these are ’heated‘ (depending on the model and program). In this case the water is heated using electricity supplied through the electrical connection. In this case the energy shown on the energy rating label is only electricity.In the case of the supplementary connection, the dishwasher draws in hot water for every fill. The Standard determines the total energy used by the appliance which in this case is the sum of the electrical energy used (mainly for pumps and motors but possibly some heating) PLUS the energy embodied in the external hot water drawn into the dishwasher. So, in this connection mode the energy is substantially higher as every fill uses hot water rather than only those fills where hot water is required. As the energy used to heat the water is typically about 60% to 70% of the energy used by a dishwasher, a hot connection is typically 50% more energy when compared to a cold connection (this varies by model).The energy impacts of a hot fill are a bit more complex. The Standard measures the embodied energy in the hot water but takes no account of the efficiency of the hot water system that produces the hot water. This is because hot water systems are many and varied and there is no typical arrangement. Another consideration is that the fill volume for dishwashers is now so low that the first one to two litres from a hot inlet is likely to be cool and require heating in any case.
Should I connect my dishwasher to a cold or hot water supply? In the case of a dishwasher, it is generally recommended that the appliance be connected to cold water where only a single water connection is available on the appliance. The prevalence of a single connection and the low fill volumes for each fill means that the cost advantage of hot fills is mostly lost. The exception would be where a solar or gas storage water heater is located close to the dishwasher.Connection to an instantaneous gas water heater is often not very effective because of startup losses. Start-up losses occur because it takes some time for an instantaneous water heater to detect the flow of water and to start. This can result in up to 2 or 3 litres of cold water passing through the water heater before the water gets heated.Another source of losses is dead water in the hot water supply pipes which cools between draw-offs (this depends on the plumbing configuration in the particular installation). In the case of instantaneous water heater these losses could account for 3 or 4 litres of cold water entering the dishwasher for each fill. Therefore the dishwasher is not likely to get very much hot water for each fill from the water heater and will heat the water internally in any case.
Should I connect my clothes washer to a hot water system? In the case of a clothes washer, it is generally recommended that the appliance be connected to both cold and hot water where dual connection is available on the appliance. Purchasers should take special care when selecting a new appliance to make sure that it has dual connections, if this is desired. If the appliance has only a single water connection, there is usually no option but to connect to cold water and let the appliance heat the water internally. Note: it is not usually possible (or recommended) to connect a clothes washer to hot water only.Connection to hot and cold water (dual connection) offers the advantage of using low cost and/or low greenhouse hot water supplies such as gas or solar for the clothes washer. For a warm wash, typically 80% of the total energy consumption is required to heat the water.Care is required when connecting an instantaneous gas hot water system to a clothes washer. Most clothes washers now take in water in small amounts many times over a 10 minute period during the wash fill (this approach is used for load sensing systems) – this means that an instantaneous system will be required to start and stop many times, which can be quite inefficient.
Should I wash my clothes in cold water? Washing clothes in cold water will save a substantial amount of energy. As about 80% of the energy in a warm wash is associated with heating water, cold washing uses less than one quarter of the energy for warm washing.If the washer shows a cold water energy on the energy rating label then it should be capable of a cold (or cooler) wash. Many front loading washers are not capable of washing in cold water – make sure you check the minimum wash temperature available if this is an important aspect for you.As stated on the energy rating label, the washing performance of the machine is not measured or guaranteed on cold water washing. There are issues associated with cold water washing of which you should be aware.Washing performance (soil removal) in cold water will almost always be worse compared to washing in warm water. This is because bleaches (where present) are more active at higher temperatures while soils and grease (and the detergent which is used to remove these) are also more soluble in warmer water. Some detergents with enzymes require certain minimum temperatures for these enzymes to activate, so check the manufacturer’s instructions. So called cold water detergents do vary somewhat in their performance in cold water. Most detergents also use fluorescent whitening agents (or optical brighteners, which absorb UV radiation and re-emit this as light in the visible spectrum) to enhance the appearance of the load after washing.A good source of information on cold water washing and detergents is Choice magazine (published by the Australian Consumers’ Association) which is available in many libraries, or by subscription.Another consideration for users is that the cold water temperature varies by season and also by region. For example, cold water in Queensland in summer could be as warm as 25C which is fine for cold water washing. In Victoria or Tasmania in the middle of winter, cold water could be as low as 10C at times, which would result in a much poorer washing performance. So you may need to adjust the machine settings or program to suit the local conditions. Some machines have an option of setting the temperature of the wash temperature to a specified level by automatically mixing hot and cold (depending on the inlet temperatures) which is a good way to overcome issues with seasonable temperature variations.Of course the cost of hot water varies a lot, depending on fuel type and tariff, so the cost savings from washing in cold water will vary. The interactive appliance product listing allows you to vary the tariff of hot water to give you an estimate of the total cost of warm water washing in your region.
Do dishwashers and clothes washers get rated for water savings? Yes. All dishwashers and clothes washers should have a water efficiency label attached (part of the WELS Scheme) when offered for sale in retail outlets. This label shows a water star rating and the water consumption per load. The WELS website contains a database of all clothes washers and dishwashers on the market.The water consumption of clothes washers and dishwashers is no longer shown on the energy rating label, but information on cold and hot water consumption is included in the interactive listings for these products on this website (click ’show comprehensive information‘ to display this data within a clothes washer or dishwasher listing). As noted above, water consumption information is also shown on the WELS website and on the WELS label.