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How we test dishwashers

We put our dishwashers through a series of rigorous tests to bring you results you can rely on.

stacking shallow bowls in dishwasher

It's not surprising that many dishwashers come through our test labs. Since we can compare them all side by side, we've got the testing down to a fine art with many of our testers having over a decade's testing experience.

We assess how well the dishwashers can remove food such as oats, spinach, egg yolk, baby cereal, butter, tomato juice and tea stains that have been dried overnight, and without being rinsed first. Our test is based partly on the current Australian standard and partly on the IEC Draft standard.

But whatever our experience may be, it's you – our members – that guide how we test. How do we find this out? By asking you.

Every few years, we send out surveys, or we get you to take photos of your dishwasher load to see how you load your dishwasher and what you put in. We'll ask you what you put in your load, what programs you run, what features you think you need, and what is on your wishlist. All those results guide our test methods, which is why they change every once in a while – when you change your habits.

Our expert testers

With their 30-plus years' experience in the dishwasher laboratory, we're proud of our expert testers. They've seen all kinds of features and builds of dishwasher come through the labs, but one thing never changes – they need to get crockery and cutlery clean! We focus on the basics so that when it's time to buy, you can be sure they work well.

On top of this, many of our testers sit on standards committees, both national and international, so we keep up to date with how labs and manufacturers are changing the standards, and also give consumers a voice in this forum, where sometimes only government and industry are represented.

How we choose which dishwashers to test

Why do we choose one dishwasher over another? There are a number of reasons for this, but our priority is to test what you will see in the shops. That means that sometimes we might not cover that one brand that has one model that's sold 100 samples in Australia, and instead focus on the big brand models that you'll most likely see in the retailer. How do we know what's in retailers? We check market figures to see what's selling well. We'll also include models that you've requested; if a lot of members want it, we're going to test it.

When we know what you want, our buyers go out and use your member funds to buy the dishwashers from a variety of retailers, then bring them in as-is – this means we get what you'd get, so we can be sure the results are what you'll find, and not 'tweaked' in any way.

How often does CHOICE test dishwashers?

Along with washing machines, we test dishwashers every four to six weeks, and we tend to test in batches of six. We do this because manufacturers are constantly releasing new models into the market. We've seen some manufacturers keep a model in the market for a few months, and others for six years. So the turnover for some is quite frequent, while others are happy to have their products in the market for a long time. Brands that have been in the market for a long time tend to release less frequently. Newer brands seem to be releasing more frequently, perhaps looking for the best combination of features.

How does CHOICE test dishwashers?

We don't just use any old crockery and cutlery for our dishwasher tests. We load them based on a modified International Electrotechnical Commission (IEC) draft standard, which resembles what you're likely to put into your own dishwasher at home.

Our testers check how well the dishwashers tackle a full load of dirty dishes by measuring out and placing equal amounts of steam-baked oats, egg yolk, spinach, baby cereal, butter, tomato juice and tea on our standardised set of crockery. They also put egg yolk onto cutlery. Each of these 'soils' tests different aspects of the dishwasher's performance.

It's all then left to dry for 15-18 hours before being loaded into the dishwashers, washed (using the sensor wash if the dishwasher has one, or a normal cycle if it doesn't) and dried. The testers use a standard detergent powder, specified in the Australian Standard. Each dishwasher is tested at least twice and the scores are averaged. Testers also measure the amount of water and energy used in a cycle.

Test program selection

If a dishwasher has an auto program, we select it over the normal program. We do this because an auto or sensing program should be designed to give optimum results for every wash. You're probably also paying extra money for this feature, as the base model won't normally have it. If there isn't an auto program, we test on the normal program, as this is what our members tell us they use the most. (For more about program options and features, see our dishwasher buying guide.)

Why do CHOICE results often differ to those on energy and water labels?

For the mandatory energy and water labels (the star rating stickers on the machines), the test can be done on any program nominated by the manufacturer as long as it's stated in the product literature that it's designed to wash a normally soiled load at rated capacity. The test is also based on the Australian Standard load (not the IEC load), which we've found is not particularly relevant.

We test based on how our members use their dishwashers at home (the normal or auto program), to get real-world results.

Dishwasher test criteria explained

Overall score

The overall score (see our dishwasher report) is a combination of the washing, drying and energy efficiency scores for the normal or auto/sensor wash program, weighted as follows:

  • Washing performance (65%)
  • Drying performance (25%)
  • Energy efficiency (10%)

Washing performance

We assess how well the dishwashers can remove food such as oats, spinach, egg yolk, baby cereal, butter, tomato juice and tea stains that have been dried overnight, and without being rinsed first. Our test is based partly on the current Australian standard and partly on the IEC Draft standard.

Drying performance

This score reflects how dry the dishes are 30 minutes after the normal cycle finished. During this time the doors are left closed, unless the dishwasher has an automatic door opening function that is activated at the end of the program.

Energy efficiency

This is based on the amount of energy used per place setting by the dishwasher on the tested program. The less energy used, the higher (better) the score.

Noise level

These are the maximum noise levels recorded during the normal program, measured one metre away from the dishwasher and one metre above the ground. You'd be aware of all these dishwashers running in the background.

Reliability and Loyalty We're often asked why we don't score products on their durability, or how long they last. The reason? Durability testing is a very long and costly process, and by the time we got results for a given model, it probably wouldn't be on the market anymore. Instead, we survey our members, asking whether they've had any problems with their dishwashers, and whether they'd buy the same brand again. To see which brands fare best, check the reliability and loyalty scores in the Dishwasher reviews table.

Our test lab

We maintain a lab that is up to date with the latest reference machines and calibrated measurement tools for our testers to bring you the right results.

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