Which is more economical, To boil a cup of water in a 900 watt microwave oven or a kettle which needs more?

Question

water to cover the element. ??

Answer 1

My husband drinks tea and I don't and boiling a kettle seemed a waste so what I done was I went into Argos and bought a travel kettle that only holds 2 cups of water. It uses hardly any electricity and does the job. For the standard sized kettle you have to have so much water in it to cover the element which is usually about 2/3 cups. So I would say the first would be a travel kettle, the second would be the microwave oven and last the regular size kettle.

Answer 2

The most efficient would be an immersion heater or other resistance heater where nearly all of the heat produced is transferred to the water. In a microwave oven, all of the microwave energy is transferred to the water, but not all of the incoming electrical energy is converted to the microwaves; some is lost as waste heat. A kettle on a stove burner captures a lot of the heat from the burner, especially if it covers the whole burner. But you can tell by feeling the air around the kettle that some is still lost to the surrounding air, and is left in the hot element after you are done heating the water.

Among the practical choices, I'd pick the kettle over a gas burner. You at least get all the chemical energy in the gas, without the losses from converting it to electricity and transmitting that to you. If your electricity is from nuclear or hydroelectric generation, that's another matter.

The most efficient, of course, is to have large parabolic mirrors focusing sunlight directly onto a black boiler. That bypasses the whole photosynthesis and fossil fuel process!

Answer 3

A domestic kettle is generally around 1,500 Watts and takes longer to boil.
The micro-wave at 900 Watts and in a shorter time, will be more economical.
However, the kettle will be much safer.
(Compared to electric elements which transfer most of the heat into the water, gas heating of a kettle is not very economical as so much heat is lost as it spreads out under the kettle and is lost to the atmosphere).

Answer 4

The microwave is more energy efficient. But if you can boil the kettle over a wood fire and you get the wood free, then that may be more economical than paying for the electricity.