18 Washing Machine Models Varied in Cleaning Performance Saving Water and Electricity Cannot be a Dual Win

16 November 2020
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18 Washing Machine Models Varied in Cleaning Performance Saving Water and Electricity Cannot be a Dual Win

The Consumer Council tested 18 washing machine models of 3 different types, namely front-loading type (commonly referred as “Big Eyes”), top-loading impeller type (commonly referred as “Japanese type”), and European top-loading type. The items were tested for cleaning performance, rinsing and water extraction performance, environmental performance, noise level and vibration reduction, etc. Test results revealed that no model could save electricity and water at the same time. Comparing their performances in washing “cotton clothing”, the top-loading impeller models generally consumed less energy, with the electricity charge of 1 model estimated to be as low as $20 per year. On the other hand, the estimated electricity charge of 1 front-loading model, which recorded the highest electricity consumption, might be 13 times higher than the least energy consuming one, i.e. a top-loading impeller model per year. However, top-loading impeller models consumed the most water whereas the front-loading models and European top-loading models saved respectively about 50% and 55% water on average. As for the cleaning performance, the top-loading impeller models had the most varied performance, marking a nearly 15% difference in their cleaning ratios (the reflectance values of soiled fabrics after washing). In all, each type of washing machine has its own strengths and weaknesses; consumers should compare and made their choice carefully.

The claimed maximum washing capacity of the 18 washing machine models were between 7 and 8kg. The 10 front-loading models were commonly priced higher, from $4,190 to $8,230, while the 5 top-loading impeller models were generally priced lower from $2,588 to $4,450, and the 3 European top-loading models from $4,190 to $6,190.

Cleaning performance is the primary factor in choosing a washing machine. With reference to the test method of some European consumer organisations, the models were tested in 2 sessions, “cotton clothing” and “synthetic fibres clothing”. Test results showed the performance among different top-loading impeller models had the largest discrepancy, with about 14% and 16% difference in cleaning ratio in “cotton clothing” and “synthetic fibres clothing” respectively. 2 of the models performed the worst and scored 3.5 points only. On the contrary, European top-loading models had the least discrepancy in their cleaning ratio in “cotton clothing” (about 3%) and “synthetic fibres clothing” (about 1%). Cleaning performance of all 3 European top-loading models and 6 front-loading models were rather desirable, achieving a relatively high score of 4.5 points.

The lower the rinsing index, the less the amount of detergents remained on the clothes after washing. Variation in rinsing index among the different front-loading models in “cotton clothing” session reached about 64%, while that among the top-loading impeller models in “synthetic fibres clothing” session was around 50%.

The water extraction performance of a washing machine will affect the time required to hang-dry the laundry. In the session of “cotton clothing”, the remaining moisture content of clothing among front-loading models vastly varied, with a 42% to 112% increase in weight of the same pile of dry clothing, while the other 2 types of models varied less. For the session of “synthetic fibres clothing”, the remaining moisture content of the 3 types of models ranged from 28% to 53%. Comparing the front-loading models only, 1 of the models with spinning speed of 800rpm performed similarly as another model with 1,200rpm in extracting water, reflecting that the water extraction performance of washing machines does not solely rely on spinning speed, but is also subjected to factors such as the duration of water extraction and product design.

If duration of the wash cycle is an important consideration, the top-loading impeller washing machines models may be a better choice, since all models took at most about 1 hour to complete the wash cycle. However, the wash cycle in “cotton clothing” session of other 2 types of models commonly required longer time, with 7 models taking over 3 hours to complete.

A “quick” cycle is available in some models for small amount and less dirty laundry. Nevertheless, the test result revealed that among the same type of models, the longer the washing phase the cleaner the laundry. Taking the front-loading models as an example, 2 models with the shortest washing phase of less than 8 minutes to wash 1 kilogram of “cotton clothing” had inferior cleaning performance to most of the other front-loading models. On the contrary, another model with the longest washing phase of about 29 minutes for each kilogram of laundry, had more desirable cleaning performance.

Other than the spinning speed, product design is the main factor affecting the reduction of noise level and vibration. The test results showed that 1 top-loading impeller model (800rpm) and 1 European top-loading model (1,200rpm) scored the lowest of merely 2.5 points.

Environmental performance of products is a growing concern of consumers. Under the Mandatory Energy Efficiency Labelling Scheme, the top-loading impeller type washing machines have a tighter grading standard than the other 2 types. Despite all models having a grade 1 energy label, the test revealed that models of the same type recorded a large disparity in energy consumption. For example, in the “cotton clothing” session, grade 1 front-loading models experienced nearly 60% discrepancy in energy consumption in washing each kilogram of clothing. Assuming doing laundry 260 times per year with $1.2 as the unit charge of electricity, the energy consumption among models in “cotton clothing” session was computed to cost a big thirteenfold difference each year. The top-loading impeller models consumed the least energy with electricity charge of $20 to $47 per year, but that of the front-loading models could be ranged from $134 to $281, and European top-loading models were billed from $135 to $209. The Council recommends EMSD to further raise the energy efficiency grading standard of washing machines so as to encourage traders to introduce products with higher energy efficiency.

The test clearly revealed that it was difficult for washing machines to save electricity and water at the same time. Although the top-loading impeller models consumed the least electricity in both washing sessions, they consumed the most water requiring around 23.9L and 37.7L of water on average to complete each kilogram of laundry for “cotton clothing” and “synthetic fibres clothing” respectively. On the other hand, models of the other 2 types on average conserving about 50% and 55% of water than top-loading impeller models.

In addition, the tested models only provide 2 to 3 years of “whole machine warranty”. The Council calls on manufacturers and traders to supply products with a longer warranty period and lower renewal fees as well as repairing charges, in order to enable consumers to extend product lifespan by repairing, hence joining hands to promote sustainable consumption.

When using washing machines, consumers should pay heed to the following:

 - Keep washing machines away from dampness. If there are no children at home, leave the doors open after washing to prevent moisture build-up;

 - Washing machines should be plugged in an individual socket;

 - Always try washing with full load, but not exceeding the limit stated in the instructions;

 - Using excessive amounts of laundry detergents might not help with the cleaning performance, but might result in excessive foam and affect the operation of washing machines;

 - Some washing machine models are equipped with “Eco” washing program which could achieve better water and electricity saving;

 - For maintenance, clean the detergent dispensers, drain pump filters, lint filters, and the rubber seal of machine doors regularly etc., as well as to clean the dirt and debris accumulated;

 - If the washing machine takes longer time than normal for inflow of water, check whether the water supply hose and the filter are blocked;

 - Do not leave children playing next to the washing machine, given that the child lock function of washing machines is just an aid.

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