How we test washing machines

Choosing which machines to test

As much as we’d love to, we can’t test every washing machine on the market – testing is expensive and time consuming, and we have a limited budget.

Instead, we regularly survey the market, and ask manufacturers which models will be deleted, which are staying available and what new models they plan to release in the near future. Then we choose a representative selection of machines for testing, including both cheaper and more expensive models, front and top loaders, and any models with interesting technical innovations.

If you don’t see the model you are considering buying in our test results, then try and identify a similar model by the same manufacturer, and pay attention to our reliability and satisfaction results – if you choose a brand that scores highly in these, you’ll likely end up with a good machine, that will also last you a long time.

Overall score

Our overall score combines test performance (how well the appliance works) with predicted reliability (how likely models from the brand are to remain free of faults) and owner satisfaction (how likely owners of the brand are to be very satisfied).

We’ll only recommend appliances you’ll love to own, that work well and keep working well for a long time.

Test performance

It’s no good if a product lasts for several decades if it doesn’t work well in the first place. A disappointing product will soon become unloved and unwanted. For this reason, our independent lab testing forms an important part of our overall score.

Our washing machine test is based on the standard AS/NZS 2040:1998. We use machines filled with 3.5kg loads, as our research has indicated this is the average load size in New Zealand.

Our test includes dirt removal, rinsing, gentleness, spin efficiency, noise, and water and electricity use.

Dirt removal

Specially prepared swatches of fabric, pre-stained with a specific amount of dirt, are attached to a standard wash-set of linen garments. These swatches are the same as those used for international standards tests.

A 3.5kg load is then washed on a standard cotton cold cycle at 20°C. Laundry detergents are formulated to work best at low temperatures, and in our testing, we’ve found that warm washes only make a marginal difference to dirt removal.

After the wash, the swatches are removed and analysed using a spectrophotometer – this machine detects the amount of light reflected from the swatch to calculate how much dirt has been removed. In simple terms, the whiter the swatch, the more dirt has been removed.

Rinsing

We add a special marker chemical to the wash and take a water sample at the end of the final cycle. The amount of this chemical left in the rinse water determines how well the machine has rinsed out dirt and removed detergent residue.

Gentleness

To check how gentle a machine is on your clothes, we attach swatches of an easily frayed fabric to the test load. We measure the swatches before and after the wash. The less fraying there is, the gentler the machine and the higher its gentleness score.

Spin efficiency

We weigh the load before and after the wash. The closer the final weight is to the original, the more water has been removed in the spin cycle, and the higher the spin efficiency score. Testing is done using a machine’s maximum spin speed.

Noise

No one wants a noisy appliance, so we accurately record the maximum noise level a washing machine makes during its spin cycle - from 1m away from the machine and 1m above the ground.

Water and electricity use

We measure and record water and electricity use for the standard cycle. This often differs from the water and energy label consumption figures, so remember to compare results between tested models using our figures.

Predicted reliability

It’s reasonable to expect a new appliance to remain fault-free for at least the first 5 years. Our predicted reliability won’t tell you whether the washing machine in your laundry will spring a leak tomorrow, but it does show which brands make models that are less likely to fail.

Owner satisfaction

Satisfaction is important – no appliance should be a source of buyer regret. Appliances with very satisfied owners are more likely to get cleaned regularly and maintained well. Their owners are also more likely to get any faults repaired, rather than look for a quick replacement.

Repairability (coming soon)

Older appliances are more likely to go wrong, but common faults should be repairable. Repairs should be affordable and convenient – parts need to be easy to find at a reasonable cost, instructions should be available, and repair shouldn’t need hours of expert labour.

We haven’t been able to assess the repairability of the washing machines we test yet. But it’s important, so we’re gathering data and forming a plan so we can start including repairability in our overall scores. It will be challenging. We’ll need to analyse the product failure data in our reliability surveys, conduct hands-on inspections to evaluate how easy products are to take apart, and investigate which brands make spare parts available at a reasonable price.

Survey data 101

In our annual reliability and satisfaction survey, consumers tell us about faults that have left an appliance they own unusable or mean they’ve had to change how they use it. We also ask them how satisfied they are with the appliance. We use their data to produce our predicted reliability and owner-satisfaction scores.

We use a statistical test to rate the relative performance of each brand. Compared to data we have for all products (of the same type) in the survey, we rate each brand with highest, high, average, low or lowest reliability and satisfaction. You can compare the rating of different brands for the same product type (for example, the reliability rating for Miele and Haier washing machines), but you can’t compare the results for different product types (for example, satisfaction of LG TVs and Samsung phones).

We analyse brands that get at least 30 responses in our survey. That means there are some brands we can’t analyse because we don’t have enough data. For those brands, we assume they have  average predicted reliability and owner satisfaction.

Our current data is based on responses for 3,413 washing machines in our 2022 survey.