Most products have two sets of test results – front-loader and top-loader. For this test, both the front- and top-loader were set on “normal” wash cycles — the type of wash cycle an average consumer is likely to choose to wash an everyday load.
How we test
We wash specially stained fabric swatches in our lab. We add bath towels to approximate a typical load of washing. These swatches are used by detergent companies and consumer organisations worldwide.
One swatch is stained with nut oil, milk and a colour pigment. This swatch is used to measure performance on “everyday grime”. The other swatches test a detergent’s cleaning ability on nine common stains: collar and cuff grime; grass/mud; olive oil; make-up; chocolate ice cream; baby food; and blood.
We measure the recommended amount of detergent for a normally soiled load and used this to wash test loads at 20⁰C, the most common wash temperature. Each load contains two swatches of each stain and each detergent is tested twice. Products suitable for both top- and front-loaders are treated as two separate products and are tested in each type of machine.
We test detergents in a “normal” wash cycle, which is what a consumer is most likely to choose for an everyday load. After washing, we measure how much of the stain was removed from each swatch using a spectrophotometer.
The cost per wash is as measured during testing using the manufacturer’s recommended dose for a regular wash (but may vary from the manufacturer’s stated number of washes per pack).
We include a wash using only water as part of our laundry detergent tests. In our front-loader test it earned an overall score of 55%, equal to the lowest-scoring product. In our top-loader test, water achieved an overall score of 44% — which was 1 point behind the lowest-scoring product.
Cold vs warm water
In previous tests, we’ve tested some detergents using warm water (40°C) to check whether there’s any difference in performance.
Overall, we saw a small improvement in dirt removal when using warm water, but it depends on the type of stain you’re trying to remove. Some detergents perform better in cold water than warm with some stains. For example, blood stains tend to set in warmer water so you’re better off tackling these with a cold wash.
Top vs front loaders
Most manufacturers produce a detergent suitable for both front- and top-loading washing machines, but our testing shows stain removal results won’t necessarily be the same in both types of machine.
This is mainly due to differences in the wash cycles. Top-loaders clean your clothes in less time by vigorously swirling them back and forth in a large amount of water while front-loaders do the job slowly and more thoroughly, by turning your clothes over gently in a smaller amount of water.
Top-loading machines generally don’t perform as well as front-loaders when it comes to stain removal. For this reason, we set a lower benchmark for recommending top-loader laundry detergents than for front-loader laundry detergents.
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