There are several different ways to heat and boil water in our kitchens. as stove tea kettles are a more traditional option, while electric tea kettles heat water faster and use less energy.
To prove this, we ran an actual experiment. After all, “One accurate measurement is worth a thousand expert opinions.”
In this article:
- Which kettle uses less energy to boil water?
- Which kettle boils water faster?
- Which kettle costs less to use?
- Can variable electric kettles save energy?
- Which kettle is best overall for the environment?
Quick Summary and Stats:
Energy Efficiency
- An electric kettle uses less energy than a gas kettle to boil water.
- An electric kettle can boil about 3 liters of water with the same amount of energy it takes a gas kettle to boil 1 liter.
- The world brews about 3.7 billion cups of tea each day. The energy savings from using an electric kettle over a gas kettle would be about 4.6 million kWh. This is enough energy to power about 158,000 homes per year.
Time
- At 100 mL of water, both kettles take about 1 minute to boil. However, if you are boiling more than about 300 mL, the electric kettle will boil water much faster.
Cost
- The difference in cost between the kettles is only about 1-3 cents, even if you pay high prices for electricity and low prices for gas, and visa versa.
Environment
- An electric kettle is best for the environment in most cases. A gas kettle is only the best option for the environment where electricity is generated by dirty sources of energy.
WHich Kettle Uses Less Energy To Boil Water
An electric kettle can boil water more efficiently than a gas kettle. In fact, a gas kettle can use as much as 2-3 times more energy than an electric kettle, depending on how much water you boil. This is true no matter if you want to boil only 100 mL of water or 1 L of water.
To figure this out, I poured 100 mL of water into an electric kettle as well as a stovetop kettle. I heated the water to boiling point in both kettles and recorded how much energy was used.
For the gas kettle, boiling point was determined when the kettle first started to whistle. To measure the amount of gas needed, I used the gas meter in my home. To measure the amount of electricity used I used a Kill-A-Watt meter.
Next, I increased the amount of water in each kettle by 100 mL and ran the experiment again and again until I reached 1,000 mL, or 1 liter.
With just 100 mL in each kettle at the start, the electric kettle used about 0.03 kilowatt hours and took about 60 seconds to boil.
Interestingly, even from the very beginning, the electric kettle used less energy than the gas kettle. At first, the difference was only about 0.01 kWh to boil 100 mL of water.
By 200 mL, the electric kettle used about 0.03 kWh less than the gas kettle, and by 1 L of water, the electric kettle used about 0.16 kWh less energy. This means the electric kettle could boil nearly 2 extra liters of water with the same amount of energy as the gas kettle uses to boil 1 liter.
For reference, you can make a cup of tea with about 300-400 mL of water, assuming some will evaporate before you can use it. The world brews about 3.7 billion cups of tea each day. The energy savings from boiling enough water for all of these cups of tea in an electric kettle over a gas kettle is about 4.6 million kWh.
This is enough energy to power about 158,000 homes per year. But don’t stress over this too much. The amount of energy your home uses in a few seconds for heating is probably more than boiling a single cup of tea. So, if you are looking for ways to save energy, an electric kettle can certainly help however, there are far more impactful ways to do so.
In fact, when it comes to making a sustainable cup of tea, boiling water is not the most impactful part. Finding local tea that avoids intercontinental transport uses far more energy. Of course, that energy is used outside of your home, but the point is the same.
Which kettle boils water faster?
At 100 mL of water, both kettles are able to boil water in about the same amount of time. However, if you are boiling more water than about 300 mL, the electric kettle will boil water much faster.
At just 100 mL, both kettles took about one minute to boil. By 400 mL, the electric kettle took about 2 minutes to boil, while the gas kettle took about 3 minutes to boil. One minute is not a very long time, but it is 50% more time.
At 1 L, the electric kettle boils water about 1.5 minutes faster than the gas kettle.
Keep in mind that these values, as well as the energy use values, are based on stopping the gas kettle as soon as it started to whistle steadily. If you’re like me, you probably aren’t waiting around for the kettle to boil and end up using a bit more energy and time. Still, the gas kettle used more energy and took more time.
Which kettle Costs Less to Use?
The cost to operate each kettle will depend on how much electric and gas costs in your area. Based on the average electricity and natural gas costs in the US, the cost to use each kettle is almost identical.
The electric kettle may cost 1-2 cents more to boil each increment of water.
An electric kettle may be the cheaper option if:
- Your electricity costs less than about 23 cents/kWh and
- Your gas costs greater than or equal to about $0.014/cubic foot.
A gas kettle may be the cheaper option if:
- Your electricity costs more than about 23 cents/kWh and
- Your gas costs less than about $0.014/cubic foot.
For example, my electricity costs about 24 cents per kWh and my gas costs about 1.4 cents per cubic foot. At these rates, there are only very small changes in the overall costs to boil each increment of water, with gas being 1-2 cents cheaper.
However, even if your electricity and gas costs vary from the average, it’s not likely to make a big difference in the overall costs.
Even if you compare the costs to run both kettles using the highest electricity costs in the country, as well as the lowest gas costs, the difference is still only a few cents. The difference is still so small that if you boil water with the gas kettle every day, you’ll only save about $3-$7 per year.
The opposite is also true. If you compare the lowest electricity costs and the highest gas costs, the electric kettle is also only a few cents cheaper than the gas kettle. This is also a very unlikely scenario, as the highest gas costs in the country are found in Hawaii. The gas costs there are nearly double the next highest state, however, Hawaii is also home to some of the highest electricity costs in the country.
In other words, both kettles have the opportunity to be the more cost effective option, but only by a very small amount. At best, you’ll likely only save a few dollars per year by using whatever your most cost effective option is
This is also true if your home is powered by solar power. In that case, the savings would be another cent or two higher because the energy used to boil these volumes of water is small.
How Much Energy Does a Variable Kettle Save?
A variable electric kettle allows you to select the temperature you want the water to be heated to. As a result, you can choose to heat water to lower temperatures than a gas kettle. Depending on the temperature you select, you save different amounts of energy. For example, heating water to just 165 degrees, saves about 33% of the energy compared to boiling.
In the context of tea, this could result in significant energy savings, as many types of tea don’t require boiling water to brew.
Green tea, which is one of the more popular types of tea, only needs to be brewed with a water temperature of about 165 degrees. It’s even claimed to taste better when compared to tea brewed with boiling water.
It’s impossible to know when the water has reached 165 degrees without a thermometer. You’d either have to let the kettle boil or guess when to stop it. An electric kettle can shut off when the water is fully heated.
WHICH KETTLE IS BEST FOR THE ENVIRONMENT?
Just because an electric kettle uses less energy, it doesn’t mean it’s better for the environment. Under the average electric grid emissions, the gas kettle produces less emissions. But, this is only true for volumes of water of about 300 mL or less. For reference, this is only enough water to make a somewhat small cup of tea.
If your electricity is generated from cleaner sources of energy than the national average, it’s likely the electric kettle will produce less emissions at all volumes of water. If your electricity comes from the most polluting areas, it’s likely your gas kettle will be the less polluting option.
In reality, power plants use natural gas more efficiently than our stovetops. This may mean an electric kettle is less polluting, even under the average grid conditions.
Keep in mind however that a gas kettle puts emissions directly into your home, while an electric kettle produces its emissions at the generation site. In some of our other tests, we show how gas stoves contribute to indoor air pollution.
Summary
You can lower your energy use by simply using an electric kettle over a gas kettle. You can lower your energy use further by using a variable electric kettle. Our recommended variable tea kettle is the Adiago Electric Kettle. Variable kettles allow you to heat water to a range of temperatures.
An electric kettle is often the better option to lower your carbon footprint, unless your energy comes from polluting parts of the country.
The cost difference between the use of both kettles is very small, even in extreme (and possibly non-existent) conditions.