How much does it cost to boil a kettle? Experts tap in on the price of boiling water

If you're getting high energy bills, you might genuinely have started asking yourself: how much does it cost to boil a kettle? Trivial as it might seem, we flip the switch on our kettles far more times than we dare to divulge and with an estimated 165 million cups of tea consumed each day in the UK, it's no surprise we're pointing fingers at this small appliance.

The best tea kettles are energy-efficient and have a multitude of features that help you use less energy. Most have minimum and maximum fill lines and smart limescale filters, and more models now boast variable temperature controls – so you don't burn tea leaves or coffee grounds – as well as keep-warm and automatic functions to keep your H2O warm, but not unnecessarily hot, or to switch the unit off/on standby when not in use. But is it enough to keep costs down every time you make a cuppa?

We spoke to the experts who gave us their insight on the price of using an electric kettle and how best to use it if you're trying to lower your electric bill and keep energy usage down in general.

How much does it cost to boil a kettle in the UK?

'With an estimated 95% of British families boiling their kettle at least once a day. 40% of families do so more than five times a day. The exact costs will vary on the size/power rating of your kettle plus your electric tariff cost,' says Matthew Jenkins, energy expert, MyJobQuote.

'The average 2-litre kettle has a power rating of 3 kilowatts per hour (kWh), although it must be noted that it will never take a whole hour to boil your kettle! Instead, boiling a kettle for an average of 4 minutes uses 0.225kWh. As the average cost per unit of electricity now is £0.28, to work out the costs you must do the following sum:

'Power used (in this case it’s 0.225kWh) x cost of one kWh in pence (0.28)'

This means it costs the following:

• To boil a full kettle (2 litres): £0.06p
• To boil a half-full kettle (1 litre): £0.03p
• To boil two cups of tea (500ml): £0.015p

'Naturally, it is more expensive to boil a full kettle than a half-full kettle, as there is less water that needs to be heated, meaning less energy is used. This is why it is so important not to overfill your kettle and only fill it with the amount of water you need.'

3 energy-saving kettles to buy

How much does it cost to boil a fresh kettle vs. reheating water?

'The cost for reheating water you’ve recently boiled will not be as much as boiling a fresh kettle from scratch,' confirms Jenkins.

'It is a difficult cost to work out exactly, as it depends on the amount of water in the kettle, how long the water has been left to cool and the energy efficiency of your kettle. If you have left your boiled water for longer than 10 minutes then it will most likely need to boil entirely again, costing the same amount as before.'

What factors affect how much it costs to boil a kettle?

Ever notice white or off-white shards in your kettle, or worse still floating about in best travel coffee mug on the way to work? Chances are you need to clean your kettle. Though there are advantages of living in London and the surrounding home counties – hard water isn't one of them, as it means limescale is likely to build-up more quickly in these areas.

To ensure your kettle is working in tip-top condition, make sure you know how to descale a kettle properly. This can be done using vinegar if you're worried about harsh ingredients in shop-bought solutions.

'Having limescale in your kettle is a common issue, affecting around 60% of the UK, especially in the South East of England.' says Jenkins.

'If limescale is present in your kettle then the kettle uses more energy to heat up the water, resulting in more expensive energy bills. Descaling the kettle means your kettle uses less energy to heat up limescale and instead, uses that energy to heat up water.

'Overfilling your kettle is an unnecessary cost. If you are in the habit of filling your kettle all the way when you only want one or two cups of tea, then this can add up throughout the year. Being mindful of how much water you use means you will only pay for exactly what you use.'

Thames Water's top tips on reduce the effects of hard water scale?

We spoke to Andrew Tucker, water efficiency manager at Thames Water who is a fountain of knowledge for all things water-related. So if you've got higher traces of minerals like magnesium, calcium and potassium in your water, you might want to soak up these money-saving suggestions:

• Reduce the temperature of your hot water to 60 degrees Celsius
• Put a steel scale collector in your kettle
• Empty your kettle if you’re not using it for a while
• Install an electric descaler. Thames Water recommend Scaleguard

Is it cheaper to boil a kettle for cooking, or bring cold water up to the boil?

'Economically, it costs less to start with hot water than to bring cold water up to the boil,' confirms Jenkins.

'Although you may (understandably) think using a kettle to boil the water and then putting it on the hob will cost more, by including an extra appliance in your cooking, you reduce the amount of time the water needs to boil.'

'Even if you place just enough cold water onto the right hob, it will still take an average of 7 minutes to boil, whereas boiling in an electric kettle typically takes just 4 minutes.'

Does the kettle use a lot of electricity?

'Generally speaking, a kettle is not the biggest electricity cost in your kitchen, and if you use it correctly it can be used relatively inexpensively,' says Jenkins.

'In fact, using a kettle to boil water is 80% efficient, as long as you make sure you boil the exact amount of water you need and try not to leave it plugged in when not in use, then the kettle is a convenient appliance.'

'To ensure you aren’t using too much energy, consider buying a new and energy-efficient kettle. Some older kettles have insufficient insulation, which means they take longer to boil and don’t stay warm for long enough – resulting in a need to boil again. However, energy-efficient boilers can keep the water warm for longer.'

Is it cheaper to boil water on a gas stove or electric kettle?

'As gas is cheaper than electricity (the average cost after the price cap increase is now £0.07p), it might be worth going back to basics to boil your water on the hob,' advises Jenkins.

'If you do decide to try this however you must ensure you only boil the exact amount of water you need, in a correct sized pot and on the correct sized hob. For example, boiling a small pan of water on a big flame won’t make your water boil any faster and will cost more than using a smaller ring.'

Another option that ticks the boxes for style and saving money is to invest in the best stovetop kettle. As well as being purpose-built for making pots of tea and boiling water for pasta – the options available are pretty darn cute too. The Le Crueset traditional kettles come in lots of colours to suit all types of kitchen.

Is it cheaper to heat water in kettle or microwave?

In a busy household, it's pretty common practice to use your microwave to heat up cold coffee and the like. 'Microwaves cause water molecules to vibrate, thus producing heat quickly, so it is understandable that some heat their water in the microwave,' says Jenkins.

'The average microwave costs around £0.13p to be placed on full power for 2.5 minutes so the cost is relatively inexpensive, however, it is not more efficient to use this method instead of the kettle if you are only boiling one cup. Energy-efficient kettles are much better insulated than a microwave, meaning water stays boiled for longer.'

Other ways to boil water

New and innovative technologies mean that you don't have to own a kettle or stove to get boiling water... You can get heated water at the touch of a boiling water faucet. There are pros and cons of boiling water taps of course, so it might be worth weighing up the advantages and disadvantages of a hot water dispenser for your home. But if we are merely looking at answering the question of 'how much does it cost to boil the kettle' with the 'kettle' being this smart device – it's ever-so-slightly cheaper to run a kettle each time.

Time to get 'thriftea'.