Kate Ng tested 10 kettles against London's hard water to see which performed best, and only seven made the cut. The Russell Hobbs Brita Purity Glass Kettle came out on top for its built-in filter system, while the Lakeland Pearlescent Glass Kettle was named the best budget buy.
How the kettles were tested
Ng used water straight from the tap to test each kettle and its various filters, making numerous cups of tea to judge filtering prowess. She also timed how long each kettle took to boil when full, noted how quiet or loud they were, assessed the pour, and considered how they looked on the counter.
Hard water, which contains high levels of dissolved natural minerals like calcium and magnesium, is harmless but can leave a scummy layer on tea and cause limescale buildup in kettles. Most kettles come with a filter to stop loose limescale from getting into drinks, but not many effectively deal with hard water.
Top performers for hard water
The Russell Hobbs Brita Purity Glass Kettle earned five stars for its built-in Brita MAXTRA PRO Limescale Expert cartridge, which uses a four-stage filtration process targeting limescale, chlorine, lead and copper. It boiled water in two minutes and 20 seconds and produced totally clear tea without scum. However, Brita cartridges need replacing monthly and can cost almost £40 for a six-pack at full price.
The KitchenAid Artisan Kettle also earned five stars for its temperature control and ability to deal with hard water. It features a removable mesh filter behind the spout that is finer than others tested, producing a thinner film on brews. It costs £199 and takes up significant counter space.
The Graef Glass Kettle and Tea Maker earned four stars for its built-in tea infuser and precise temperature controls, including settings for green tea and filter coffee. However, brewing tea in the kettle leaves stains that are difficult to clean by hand.
Budget and design options
The Lakeland Pearlescent Glass Kettle earned three stars as the best budget buy at £39.99. It has a 1.7L capacity, the largest tested, and a built-in limescale filter in the lid, though brews still had a thick scummy layer.
The Dualit Architect Stainless Steel Kettle earned three stars for durability and an excellent pour, but it was loud and shook when boiling. The Aarke Stainless Steel Kettle also earned three stars for its sleek design and quiet operation, though it lacks a visible water level indicator.
The Tefal Includeo Kettle earned three stars as a lightweight, compact option suitable for travel or those with accessibility issues, but it performed poorly at filtering hard water. For the best results with hard water, Ng recommends using filtered water, which also reduces limescale buildup significantly.
