6 ways to save energy when boiling your kettle

When you think about it, the kettle must be one of the hardest working appliances in any kitchen. From first thing in the morning to late at night, the hot water it provides fuels our prodigious tea consumption, helps us brew a pick-me-up coffee, warms baby bottles, offers a dinner-time shortcut for boiling pasta and rice and fills bedtime hot water bottles. But while efficient in terms of time-saving, your kettle is also one of the bigger energy hogs in your kitchen. Even the best kettles are guilty in this regard, with their powerful heating coils quickly racking up the kilowatt hours.

With energy prices in the UK seeing another year-on-year increase, many of us have been left searching for different ways to reduce our electricity bill and looking at how you use your kettle is a great place to start. Our guide will show you how to quickly calculate how much energy your kettle uses and our tips and tricks will help you to get that number down, with simple changes you can make and expert insight from Isabella Forgione, a small appliance expert at online retailer AO.

How much energy does your kettle use?

Before we look at ways to reduce your kettle’s energy usage, it can be helpful to understand just how much electricity your kettle is currently consuming. To work this out, we’ll use the current average price of energy, which is 24.9p/kWh. If you’re unfamiliar with kWh as a measurement, it stands for kilowatt hour and represents the number of kilowatts of energy used by a given appliance in one hour. For example, if you run a 1,500W air fryer for an hour you should use roughly 1.5kW of energy and this 1.5kWh of energy use will therefore cost you £0.37 – for more information on this topic, you can read our full guide to air fryers energy use.

Using our favourite kettle, the Russell Hobbs Attentiv, as an example, we can see that this 3,000W kettle took 2mins 20secs to boil one litre of water when we tested it. This means it costs roughly £0.75 per hour of boiling, or 2.92p per for the two and a bit minutes it took to boil one litre of water. Looking at a lower wattage model like the Zwilling Enfinigy Pro, we can see that this 1,850W kettle, while using less electricity, took longer to boil, coming in at 3mins 45secs.

Doing the same calculations as above, we see this lower wattage model comes out to much the same price as the quicker boiler, at a cost of 2.82p to boil one litre of water. Minor differences in efficiency aside, as our Head of Reviews Jonathan Bray likes to remind us, the laws of thermodynamics mean that boiling one litre of water will always require a certain amount of energy. Thanks Jon.

6 ways to save energy when boiling your kettle

Now that we have a solid idea of how the pennies and pounds stack up when boiling your kettle, let’s look at some relatively easy ways to shave a little bit off the above figures:

1. Only boil the water you need

This is probably the one piece of advice you expect to find when researching this topic, but it pops up often because it’s a simple and straightforward way to cut down on energy usage. Small appliance expert Isabella says: “To save energy, only boil what you need. Overfilling the kettle is one of the biggest energy wasters. Meaning if you’re only making one cup of tea, only fill the kettle with enough water for that.”

As noted in the calculations above, a 3,000W kettle can cost around £0.03 per boil when you’re heating a litre of water. Overfilling a kettle will nudge that price up, with a full 1.7l kettle taking around four minutes to boil at a cost of about £0.05. Boiling a cup’s worth, on the other hand, should take less than a minute and cost a little less than £0.01. While this only equates to a few pennies here and there, with multiple boils a day being the norm in most households, it can add up to several pounds saved throughout the year.

2. Regularly descale your kettle

As noted in our kettle descaling guide, build-ups of limescale can work as an insulator in your kettle, causing the water to heat more slowly. Isabella notes: “A kettle with a high level of limescale build-up has to work harder to heat the water, meaning it uses more energy than necessary. Choosing a kettle with a limescale filter can help prevent build-up, as well as regularly descaling your kettle.” So it literally pays to follow the simple steps in our guide to descale your kettle and keep it lime-scale free.

3. Try using a variable temperature kettle

One of the things that makes a kettle so electricity hungry is the amount of energy required to bring water to 100°C. For certain drinks, like lighter coffee roasts, matcha and speciality teas, having your water too hot will cause them to burn or develop unpleasant flavours. This means that if you want to make them right, you’ll have to boil your kettle and then allow the water to cool a little. An easy way to simplify this process and to avoid the excess energy use of boiling water you only want to heat, is to get a variable temperature kettle. Models like the Russell Hobbs Attentiv and the KitchendAid Artisan allow you to select temperatures between 40°C and 100°C, helping you perfect your hot drinks and avoid wasting energy.

4. Get an insulated model with a keep-warm function

Another way to save energy when using your kettle is to avoid boiling it multiple times close together. To get more use out of every boil, you can look out for two features present in the best kettles: dual-wall insulation and a keep-warm function.

“Kettles with dual-wall insulation retain heat better, meaning the water stays hot for longer and doesn’t need to be reheated as often,” according to Isabella. In the course of our testing, we found that the Zwilling Enfinigy Pro had the best heat retention out of any of the models we tested. Its dual-walled insulation kept water at an impressive 94.6°C when measured five minutes after coming to a boil.

Isabella goes on to say: “a ‘keep-warm’ function is another great energy-saving feature, as it maintains the water at a set temperature rather than having to bring it back to the boil from cold. This is particularly useful if you tend to make multiple hot drinks throughout the day,” and because keeping water warm requires less energy than heating it up from scratch. Some of our favourite models, like the Russell Hobbs Attentiv, Bosch Styline and the Zwilling Enfinigy Pro have keep-warm functions that can keep water hot for up to 30 minutes. However, the Swan Alexa Smart Kettle is the best of the bunch when it comes to this feature, boasting a lengthy two-hour keep-warm function.

5. Look out for kettles with auto shut-off and energy monitoring capabilities

Aside from features like dual-wall insulation, variable temperature heating and keep-warm functions, we asked Isabella if there were any other good energy-saving features to look out for when purchasing a kettle.

She highlighted two features in particular: “Smart kettles use energy monitoring to track and manage electricity consumption every time you pop the kettle on. They also use precision heating to heat water to exact temperatures which can avoid any unnecessary energy use. Auto shut-off prevents the kettle from continuing to heat once the water has reached desired temperature, once again avoiding wasting energy.”

6. Try using other methods of heating

If prohibitive electricity prices have you avoiding using your appliances altogether, then a good way to save money and still get the job done is to use another source of energy. Gas is around four times cheaper than electricity under current energy pricing, meaning heating water on your gas hob could help you save in the long run.

However, while it’s generally recommended, there are added complexities. Electric kettles are incredibly efficient, as they directly heat water through their element without losing heat to the surrounding environment. Gas hobs are less efficient, because some energy is lost heating the air surrounding the flame. So while gas may be much cheaper than electricity, you won’t save any money if you use it inefficiently.

A good way to account for this difference in efficiency is to use a stovetop kettle, which is better than a pot thanks to its tight seal and efficient heating element. Another method users have had success with is heating a wide, flat pan with a thin layer of water, taking advantage of the breadth of a gas hob’s flame to heat water quickly. Ultimately, a smart meter can help you gauge which of these methods is the best in terms of keeping your bills under control.