The overall Which? test score is made up of the following star ratings, all determined by our rigorous lab tests.
How we test overall cleaning
The combined cleaning star rating is based on the wash results from our tests for both the 40°C cottons and 40°C synthetics wash programmes.
How we test water use
We measure the amount of water used by the machines on both their cottons and synthetics programmes when washing at 40°C.
How we test cotton wash
We check how good each washing machine is at removing stains when washing cottons at 40°C and when loaded to 80% of the machine’s capacity.
How we test synthetic wash
This star rating shows how well each washing machine removes stains when washing synthetic fibres at 40°C. For this synthetics test, we load each machines to its listed capacity for synthetics.
How we test rinsing efficiency
We check how well each machine rinses detergent away from clothes by stopping the machines just after the rinse phase and then analysing the remaining water for signs of detergent. We use a spinning machine to extract the water to analyse.
How we test spin dry
We weigh the clothes we wash before and after the wash to be able to judge how well each machine spins water away.
How we test ease of use
We run more than 50 ease of use assessments as part of our tests. We look at how clear the instructions are, how easy the machine is to load and to unload, we check the clarity of markings on the control panel and how easy the controls are to use. We also take a look at how easy it is to use the detergent drawer.
How we test program length
During our tests we record how long both of the wash programmes we test take to run. The star rating is based on the length of the programmes and is relative to the capacity of the washing machine.
How we test noise
We use an expert panel to listen to each machine as it fills, washes, spins and drains. Our panel listens for the normal operating noises as well as any annoying sounds the machine makes. A five star machine will be just about as quiet as a washing machine can be. A one star machine will make a lot of noise as it fills, washes and spins.
How we test energy efficiency
We record the amount of energy used by the machines on both their cottons and synthetics programmes when washing at 40°C.
