Friday, March 23, 2007


I've had this conversation a couple of time with people, and I've realised that I can't get to a satisfactory answer without some research. And I'm lazy. So I'm going to pose a question... and if I don't get a satisfactory answer here I might well send it to The New Scientist in the hope that they'll answer it.

Assuming that the cost of setting up and maintaining the infrastructure is already taken care of, which is more energy efficient: an electric kettle or a stove top kettle?


Laurent Schneider said...

the electric kettle. It require more power (but much less time)

you have interesting tests on

Rob Baillie said...

Looks like a very interesting site... I'll be taking a good look at that later.

But. I'm a developer. I'm not going to take an "It's x" without any supporting evidence :-)

When you look at a stove top kettle against an electric it seems to make perfect sense... there is a lot of energy wasted on the stove top due to the fact that the outside of the kettle is heated. With the electric kettle is used the heating element is in direct contact with the water and the kettle can be well insulated to make sure very little of the energy is lost.

So, we can assume that there is a much higher inefficiency in the use of the energy at the point of the kettle.


Electricity generation and supply is itself costly. If your electricity is supplied via a gas power station then you have some inefficiency in the generation of the electricity, and then further loss down the lines as it is supplied to your home.

However, gas supply isn't that costly in terms of efficiency. Very little gas is lost in the pipe on the way to your home.

So can we assume that the electricity supply is more inefficient than the gas supply?

If so, the question boils down to: Is the inefficiency inherent in the electricity generation and supply system higher or lower than the inefficiency inherent in the external heating of the kettle on the stove top?

Does anyone have the answer?

(Obviously, the use of an electric hob tends to change the resulting assumptions a little and leads to the electric kettle winning every time).

Laurent Schneider said...

the worst is of course to boil water without cover and use kitchen ventilation at the same time !

to find evidence, I thing you should google some more.

Rob Baillie said...

Ah, but Laurent, you miss probably the most important part of my original post... I'm lazy