Tea is one of the most popular beverages in the world with 3.7 billion cups of it being consumed each day. Preparing enough water to make all of that tea uses more energy than millions of homes do in a single year. So, finding a way to reduce the energy needed to make tea could be very impactful.
In this article, we will figure out how much energy is needed to boil various amounts of water using a gas stove top kettle and an electric kettle. With this information I’ll also figure out which has the biggest carbon footprint, since more energy doesn’t always mean a larger carbon footprint.
To do so, we ran an actual experiment. After all, “One accurate measurement is worth a thousand expert opinions.”
WHAT IS THE MOST ENERGY EFFICIENT WAY TO BOIL WATER?
In short, it depends partially on how much water you wish to boil. Gas kettles may be able to heat smaller amounts of water to boiling point, but this could be since the bottom of a gas kettle has more surface area. Otherwise, electric kettles seem to have a pretty clear lead over gas kettles.
Which uses Less Energy? An Experiment
To figure this out, I added just 100 milliliters of water to both the electric kettle and the stovetop kettle. I heated the water to boiling point and recorded how much energy was used to boil the water in both kettles.
In this case, boiling point for the electric kettle is was determined using the preset 212 F button. The kettle automatically shuts off after reaching the set temperature.
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 and 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 milliliters and ran the experiment again and again until I reached 1,000 milliliters, or 1 liter.
With just 100 milliliters in each kettle at the start, the electric kettle used about 0.03 kilowatt hours and took about 60 seconds to boil.
With one liter in the kettle the electric kettle used about 0.1 kilowatt hours to boil and took about four and a half minutes. The amount of energy needed to boil each increment of water increased pretty evenly as more water was added.
Interestingly, with just 100 milliliters of water the gas kettle was actually the better option, however the gas kettle quickly started to use more and more energy as water was added to the kettle.
By 200 milliliters, the electric kettle is already the better option, which isn’t even enough to make one cup of tea. By 500 milliliters the difference in energy use between the kettles is clear.
Which uses Less Energy? Applying To Real Life
Since we want to actually use boiling water for various purposes, it helps to consider real life uses as well. For example, if you want to boil water in order to make a cup of tea, boiling isn’t necessary for many teas.
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 fahrenheit. It’s even claimed to taste better when compared to tea brewed with boiling water.
Without a thermometer in the kettle it could be difficult or impossible to know when water has reached 165 degrees so you’d either have to just let the kettle boil or guess when to stop it. A benefit of electric kettles like the one used in this article here, not only will the kettle shut itself off when the water is fully heated, but you can select lower heating temperatures to save energy.
How Much Energy Does a Variable Kettle Save?
When I ran the experiment again only this time heating the water to just 165 degrees instead of boiling at 212 degrees my energy use was lower still. In fact, the energy use was about 30 percent lower.
Also, if your kettle doesn’t have measurement markings on it, be sure to measure out the amount of water you need first so you don’t waste energy boiling water. Heating more water than you need is also wasteful.
Which Kettle Is Best For The Environment?
While the results show that the electric cattle uses less energy this doesn’t exactly mean electric kettles are better for the environment. This is because the electric kettle could be powered by various energy sources ranging from highly polluting ones such as coal power to emission free electricity such as solar or wind power.
If your energy comes from 100% coal power it’s better to use the gas stove top kettle when comparing to boiling water in the electric kettle, even though the electric kettle uses less energy. Since the amount of emissions between an electric and gas kettle are close it means if your energy comes from pretty much anything other than 100% coal power an electric kettle is going to be the best option in terms of carbon emissions which is likely the case for most people since most areas of the world are using a mix of energy resources. Now if you’d like help figuring out how all this applies to you so you know what the best option is for you check out our app for guidance.
On one hand the energy difference between all these options is actually rather small. In fact, I found that my home uses about as much energy on heating in the winter in about 10 seconds as it does to make an entire cup of tea. However, on the other hand if all 3.7 billion cups of tea that are made each day are made using a gas kettle and they switch to the electric kettle the energy savings could be about 450 million kilowatt hours a day. This is enough electricity for about 21 million homes a year and that’s without considering you could save 30 percent more energy by heating to lower temperatures.
So to recap, you can lower your energy use by simply only preparing the amount of water you need to brew your tea so try to measure out the amount of water you need. An electric kettle is likely always going to be the best option to lower energy use and your carbon footprint. You can save even more energy by drinking and preparing tea that requires lower heating temperatures.
If you want to learn more about what makes tea sustainable including how water heating plays a role in that read this article next.
You can check out our review of the electric tea kettle here.
You can also purchase the kettle here.