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Smeg KLF04 Variable Temperature Kettle Review

A customisable experience for a discerning tea-drinker


There's no denying that the Smeg KLF04 Variable Temperature Kettle is one of the most stylish jug kettles we've reviewed, fitting in seamlessly with Smeg's other kitchen appliances. Beyond looks, this kettle also offers the performance you need, with variable temperature settings available to let you make a wide-range of drinks at the correct temperature. Its keep-warm feature is handy, too, maintaining temperature for long periods. The downside is the price, but if you want a kettle that's flexible and powerful, the Smeg KLF04 kettle is a great choice.


  • Stylish retro design
  • Variable temperature setting
  • Quiet
  • Keep-warm function


  • Pricey

Key Specifications

  • Review Price: £159.95
  • 1.7 litres
  • Adjustable temperature from 50ºC to 100ºC
  • Removable limescale filter
  • 20-minute keep-warm function
  • 27.5 x 17.1 x 22.6cm
  • 73cm cable

Smeg’s KLF04 Variable Temperature Kettle is part of the company’s range of high-end appliances. Available in eight colours, it features the 1950s retro-futuristic design for which Smeg is renowned, matching the aesthetic of the manufacturer’s fridges, toasters and coffee machines.

You can adjust the temperature to your liking, provided it’s between 50ºC and 100ºC. It offers a keep-warm function, too, which will essentially reheat your water, maintaining your chosen temperature for up to 20 minutes. But you can only activate the function during the heating process.

However, this kettle comes at a rather hefty price, meaning this kettle is best for those who are very particular about the temperature of their water.

Smeg KLF04 kettle – What you need to know

  • Boiling performance: The KLF04 takes a slightly longer than average time to boil – just under 3 minutes. The variable temperature settings produce accurate results, with a variation of around 2ºC.
  • Keep warm: The keep-warm mode maintains your desired temperature for up to 20 minutes, but you need to remember to activate it during the heating process. Without the function activated, the kettle tends to lose heat more quickly than rivals.
  • Usability: The lid opens at the touch of a button. The kettle is easy to fill and the water indicator features a useful number of markings.

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Smeg KLF04 kettle

The Smeg KLF04 kettle is stylish and hefty – but also pricey

Considering its sleek outline, the Smeg KLF04 is surprisingly heavy at just over 1.3kg (jug only). It features a stainless-steel body of your chosen colour and a comfortable, metallic – if a little fingerprint-prone – handle.

Press the button on the lid and it opens fully, albeit a little leisurely. The water indicator sits behind the handle and features clear markings at 0.5l, 1l, 1.5l and 1.7l (MAX), with two further quarter-litre increments marked by simple lines.

Other metallic details include the spout and the base of the kettle, which has all of the controls.

Related: Best coffee machines

Smeg KLF04 kettle

Pick a temperature, and the Smeg KLF04 kettle will stick to it

On one side of the base, a row of LEDs represents the available range of temperatures: 50ºC, 60ºC, 70ºC, 80ºC, 90ºC, 95ºC and 100ºC. You can pick your preferred temperature by moving the lever on the side to the left and right.

On the left side of the lever you’ll find the power button, and on the right is the keep-warm button. Bear in mind that the keep-warm button will only work once you’ve started the heating process.

If you leave the function activated, the kettle will gently boil your water every once in a while, for 20 minutes. You can cancel this at any time.

Smeg KLF04 kettle

In my tests, the KLF04 heated water to my chosen temperatures accurately, with a maximum variation of around 2ºC. The keep-warm function kept the temperature steady for 20 minutes. I only noted a drop in temperature 30 minutes after boiling, which means roughly 10 minutes after the keep-warm function had shut itself off.

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Without the keep-warm function activated, the Smeg KLF04 kettle cools down quicker than rival models

Without the keep-warm function, the KLF04 cooled down far quicker than the similarly priced variable temperature KitchenAid Artisan kettle.

After 20 minutes, one litre of water boiled at 100ºC was around 78ºC for Smeg, and 80ºC for KitchenAid. After 30 minutes, this difference had increased to 70ºC for Smeg versus 75ºC for KitchenAid, and after an hour it was 57ºC versus 65ºC.

Smeg KLF04 kettle

The Smeg KLF04 kettle heats water quietly – and you can mute its end-of-cycle sound

The KLF04 kettle proved one of the quietest I tested. It boiled a litre of water at 100ºC in just under 3 minutes while staying under 72.5dB.

But at the start and the end of the heating process, as well as when you connect it to a power outlet and when you first touch the temperature lever, the kettle will produce rather shrill sound effects.

Smeg KLF04 kettle

While this signal can be useful in a rowdier environment, it rings quite sharply in a quiet home. Handily, this can be turned off thanks to the mute function, which can be activated by pressing the keep-warm button for five seconds.

Why buy the Smeg KLF04 kettle?

If you’d like a stylish variable temperature kettle with a keep-warm function and have the cash to splash, the Smeg KLF04 could be for you. For a more affordable variable temperature kettle, however, the Sage Smart Kettle offers similar features at around half the price – albeit with a narrower range of temperatures.

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