The overall Which? test score is made up of the following star ratings, all determined by our rigorous lab tests.
How we test ironing performance
The time and effort required to smooth out creases from all the garments in our test: a cotton-blend skirt, cotton shirt and linen trousers. One star means lots of time and effort was required; five stars means this iron blitzes creases easily with little effort needed.
How we test resistance to limescale
To see how well an iron resists steam-reducing limescale, we simulate the effect of ironing for one hour a week for around 11 months, and then measure the amount of steam an iron is able to produce. High scoring irons that are tough on limescale will be steamy after this test as they are when brand new. With one-star rated irons, the steam tails off to practically non-existent levels, which makes ironing really hard work.
How we test cleaning efficiency
This rating shows how well steam levels are restored by descaling the iron following the manufacturer's instructions. The higher the rating, the closer the post-cleaning steam levels are to when the iron was new.
How we test soleplate scratch resistance
A scratched soleplate can lead the iron to snag and catch on fabrics, so we test each iron by rubbing it 20 times with a Scotch Brite scouring pad (the sort you might use to clean your dishes with). Some soleplates are so tough that our scouring pad has absolutely no effect, while others mark quickly. If there's no star rating, it means this was not part of our testing when we reviewed this model.
How we test convenience
Includes: how long it takes to start steaming and cool down after steaming, how clear the instruction manual is, how long the power cord is, how visible the water level is, how easy the tank is to fill and empty, how easy the thermostat and controls are to use, how comfortable the handle is to grip, how smoothly the soleplate glides and whether it can slide under buttons and how easy the iron is to store away neatly and tidily after use.