Dishwashers: How we test
Model selection
We start by testing the top selling models sold by each manufacturer. We also look for newly launched models or interesting machines with innovative features such as a new washing system or basket design which we know you'll be keen to find out about.
Experts
Each basket is fully loaded according to the manufacturer's instructions
Our experts work from 4.30am to 6pm when we test dishwashers. To start, we run each machine once or twice empty, then five times with clean dishes, to make sure it's working properly.
We fill each full-sized machine with 127 items and each slimline model with 97 items every time we wash. These items include dinner plates, soup plates, cups and saucers, glasses, beakers, bowls and cutlery which we stain with meat, eggs, spinach, oat flakes, tomato juice, tea and milk, and leave to dry for two hours.
Programs
We do three runs of the normal and eco programs on 20 models – that's 14,700 pieces of crockery and cutlery.
Dishwasher testing
Our testers get the plates uniformly dirty, load the machines and set them to run. Afterwards, each item of crockery and cutlery is assessed.
We measure consumption of water and electricity, as well as noise, and we assess which machines are awkward and annoying to use. This includes rating how easy it is to use the door, figure out the controls, load the dishwasher, and top up the detergent and rinse aid.
We also test a sample of machine’s intensive programs which are designed to clean extremely dirty pots, pans and dishes that would normally need soaking, rinsing and extra wash cycles to get them sparkling and clean.
We run only one test a day on each dishwasher to ensure the temperature inside has returned to normal.
Self-clean
To measure how well each model cleans itself out we spread a 50 ml mixture of cranberry jam, whole berries, and water on the inside of the door. We then let the mixture dry for 15 hours before performing a normal wash.
After the wash we inspect the the door, the crockery, cutlery, glassware and dishwasher filter to see how much of the cranberry mix is gone in order to measure how well the machine has self-cleaned.