Some kettles have a 2.2kW element. This means that they'll use less power, but also take longer to boil. An example 2.2kW kettle can boil a litre of water in 3 minutes 10 seconds, meaning that although its cost per minute is only 1.9p, boiling a litre will cost 6.3p, similar to the 3kW kettle above.
Again, heating of 1 litre of water from 20oC 100oC need 330kJ (0.091kWh) of heat. All these method provide the this amount of heat to water. If you look the kettle which will have about 90% effciency, require 0.183kWh of electricty.
Energy usage
A standard kettle uses about 3kW of power and making a single cup of tea cost less than a penny to boil according to Uswitch.
"If you're looking for an energy saving, go for the electric kettle," he said. "If you're looking for a cost saving, go for the hob." The test revealed it cost around 1.99p to boil water using his hob, and 3.94p, almost twice as much, using an electric kettle.
It is worth pointing out that hot water taps are more energy efficient and could ultimately work out cheaper, depending on how much you boil the kettle on an average day. If you only make the occasional cup of tea then it will be far cheaper to stick to your trusty kettle.
It's more expensive to boil a full kettle than a half-full kettle, because you're using more energy to boil more water. If you're boiling a full 3kW kettle, it could set you back about 42p each time, because you're using about 0.225 KWh.
While it is cheaper to use a microwave for larger quantities of water, you will save money using the kettle if you require just one cup of freshly boiled water.
Power usage – Kettles
The average kettle is between 2 and 3 kilowatts (kw). The electricity that you use in your home is measures in kilowatt hours (kWh) which is the number of kilowatts used per hour. Most people will be charged per unit of electricity so you might be charged 12p per kwh used.
Is it cheaper to boil water in the microwave or kettle? While using a microwave is cheaper for boiling larger quantities of water, it is much cheaper to use a kettle if you just want one cup of boiled water.
Compared to running a standard 2,500W kettle 5 times per day from cold to boil, the Perma Therm hot water dispenser would consume 68% less energy. It's just that good.
It depends on the microwave's energy rating and the power setting used but using the calculations above it would cost less than half a penny to run a microwave with an average of 1kWh for one minute.
It's more expensive to boil a full kettle than a half-full kettle, because you're using more energy to boil more water.
Most kettles can boil around 1.7 litres of water at a time in about four minutes. You can expect to pay 6.8p to boil a full kettle.
As we've touched on, instant hot water taps for the kitchen can use up to 50% less energy than traditional kettles. This energy efficiency does make them a more environmentally conscious choice. Boiling water taps also help cut down on water waste.
An induction stove or hot plate is about 85 percent efficient. It creates an electromagnetic current directly in a pot to generate heat, losing very little to the air.
While gas is definitely cheaper per kWh, electric appliances can work faster, reducing the amount of time you're using energy.
Microwaves, slow cookers, electric pressure cookers and air fryers all consume significantly less energy than ovens, so using these instead, if possible, will save you money.
Experts at Uswitch.com have explained how the cheapest way to boil a cup of tea is by using a covered pan on a gas hob, instead of depending on your usual kettle. This is because gas is currently cheaper to use than electricity, despite it taking longer to heat that water.
The fast answer to that question is yes. Take a quick walk around your home, and you might be surprised by how many devices are plugged into your walls. Unplugging appliances to save energy is no myth; it's a fact.
An example 55” LED TV (rated G) uses 103kWh over 1,000 hours of viewing. This means that it'll cost £35.02 when in use. A similar 55” QLED TV (rated F) uses 77kWh over 1,000 hours of viewing, costing £26.18 to run. Size up and the impact is noticeable.
Typically, though, a microwave would be slightly more efficient at heating water than the flame on a gas stove and should use up a little less energy. The reason: The microwave's heat waves are focused on the liquid (or food), not on heating the air or container around it.
A microwave uses significantly less energy than either a gas or electric oven. To use your microwave for one hour every day would cost you about half the total energy of a natural gas oven and 60% less than an electric oven.
The same kettle can boil a litre of water in 2 minutes 30 seconds, meaning that it costs 6.5p each time.