Who doesn't want sparkling windows? Here's how we test supermarket glass and window cleaners in the CHOICE lab to find out which products are effective and worth buying.
We buy window cleaners available from major supermarkets and use our laboratory for testing them. We also work out which products are the best value for money by unit value per 100mL, based on the price we paid at the time of testing.
We also include a home remedy in our testing. Our home test is made up of 1 cup white vinegar and 1 cup of water.
With a range of products on the market, what makes us choose one window cleaner to test over another? As with most of our product testing, our aim is to test the most brands on the market and what you're most likely to see in stores.
We check instore to see what's available and survey manufacturers to find out about their range of products. From this information we put together a final list that goes to our buyers. They then head out to the retailers and purchase each product, just as a normal consumer would. We do this so we can be sure they're the same as any consumer would find them and not 'tweaked' in any way.
Lab experts put each window cleaner to the test by soiling a PVC sheet with greasy dirt. The soil is able to hold more strongly onto the PVC and allows for better separation of product performance, which is why it's used instead of glass. PVC is also much thinner than glass, which is important when measuring the soil removal with the spectrophotometer.
Using a scrubbing apparatus attached, the sheet is scrubbed, with the reflectance readings measured before and after cleaning to determine soil removal.
A streak test is also carried out on each product. This is a visual assessment whereby each product is rated based on how many streaks and/or drops are left behind. The test is carried out three times and the results are averaged.
CHOICE Expert Rating
The CHOICE Expert Rating (which is what we use to determine which products we recommend) is made up of two scores:
- dirt removal (50%)
- streak test (50%).