# Microwave v Electric Kettle



## Gaothfar (6 Mar 2009)

Hi. 
As a constant drinker of tea, I wonder if it is cheaper to boil a mug of water in the microwave or in the electric kettle? The kettle requires a couple of mugs-worth of water each time to cover the element so I know there is wastage there.
Has anyone got a smart meter or one of those unit-measuring gadgets to check this out?
Much obliged,
G.


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## Omega (6 Mar 2009)

Have you considered a travel kettle? They're much smaller and a mug of water may well cover the element..... To answer your original question, the microwave should be the cheaper option.....


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## z103 (6 Mar 2009)

I think it can be dangerous to boil water in the microwave.
If you take a cup of water out of the microwave, that has just been boiled, and then throw a spoon into it, the effect can be quite explosive.


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## Dreamerb (6 Mar 2009)

Gaothfar said:


> Hi.
> As a constant drinker of tea, I wonder if it is cheaper to boil a mug of water in the microwave or in the electric kettle? The kettle requires a couple of mugs-worth of water each time to cover the element so I know there is wastage there.
> Has anyone got a smart meter or one of those unit-measuring gadgets to check this out?
> Much obliged,
> G.


No need. 

Electric kettle - probably about 2kw
Microwave - probably about 850w (0.85kw)

How long does the kettle take to boil your water? 
How long does the microwave take? 

If the microwave takes less than 2/0.85 (that's 2.35) times as long as the kettle, you have an energy saving. For a single mug, I'd guess the microwave will very probably end up cheaper.


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## NorfBank (6 Mar 2009)

Tefal do a one cup kettle. Takes 3 seconds to heat. On sale in the Newbridge outlets last time I was there.

[broken link removed]


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## gillarosa (6 Mar 2009)

Microwave cheaper, but don't you find it doesn't make a really good cup of tea? you need water to reach full boil for a number of seconds as the kettle does to help the tea infuse.


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## NorfBank (6 Mar 2009)

That Tefal one I mentioned is crap according to the learned views of AAM. 

http://www.askaboutmoney.com/showthread.php?t=61797&highlight=tefal


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## theengineer (6 Mar 2009)

leghorn said:


> I think it can be dangerous to boil water in the microwave.
> If you take a cup of water out of the microwave, that has just been boiled, and then throw a spoon into it, the effect can be quite explosive.


 

Yes it can be very dangerous


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## car (6 Mar 2009)

I got one of those socket usage readers a couple of weeks ago and am in the midst of recording all usage.  I'll try timing that this evening with electricity usage in the microwave.   To be fair Id have to put in just a cup of water into the kettle as well whic most people dont.    else Id have to put a pint of water into the microwave and leave it until boiled or boiling. which is what most kettles would have I reckon.

was in a friends house for one of those tefal 1 cups last xmas.  water just doesnt get to that boiling point to stew the tea the way a kettle does.


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## Gaothfar (7 Mar 2009)

Thanks for all the input. 
I'm inclined to think that boiling is boiling but in practice there is something different about the tea when the water is microwaved.
I'll have to carry out timing experments to find the exact difference and then multiply the saving by the number of cups in a day. 
And I have heard about the danger of boiling liquids in microwaves. The surface tension doesn't heat and leaves a cold skin on the liquid apparently. To avoid this you stir the liquid half-way through, though in practice I've never done this and have never had a problem.
I'll go now and time a cup or two.


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## Fnergg (7 Mar 2009)

Boiling water in a microwave for tea is an abomination! You are quite correct in stating it doesn't taste the same as boiling water out of a kettle although I am at a loss to provide any scientific explanation for that. It just doesn't, OK?

We also need to rid ourselves of the habit whereby when the kettle boils and there is a momentary delay while we put the teabag in the cup, we press the power button on the kettle again just to make sure it's boiled. I do it . My friends do it. It's completely stupid and it probably accounts for a huge amount of needless electricity usage. We should accept that once boiled the water in the kettle will be sufficiently hot for a long time to make repeated cups of tea within, say, a 15 minute period at least. And yet I know I will be the first to press the power switch for my second cuppa immediately after my first (I drink a lot of tea). It's all habit.

Regards,

Fnergg


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## Gaothfar (8 Mar 2009)

After exhaustive research and many cups of tea I too have concluded that tea from a microwave is just yuck.
I think that water is boiled in a microwave by shaking its molecules about and getting them in a frenzy. So when you pop in the tea-bag, the molecules are still hopping about and they boil the tea-bag as well. The problem is compounded when you add the mild as it too cooks.
So, back to the kettle.
My latest device is a felt pen mark showing where exactly one mug's worth of water goes and I fill only to this mark.
But you're right Fnergg about hitting the power button a second time - I do this repeatedly.


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## JoeB (8 Mar 2009)

Fnergg said:


> ...
> We should accept that once boiled the water in the kettle will be sufficiently hot for a long time to make repeated cups of tea within, say, a 15 minute period at least. And yet I know I will be the first to press the power switch for my second cuppa immediately after my first (I drink a lot of tea). It's all habit.
> Regards,
> Fnergg



No way.. the water will only stay hot enough for 30 seconds or so, any longer than that requires a re-boil...

After 15 mins the tempature of the water would probably be <85 or 90 degrees!

I also hit the button far too much..  even if it has only taken 15 seconds to get the cup and t-bag I will also re-hit to get the water totally boiling...


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## Fnergg (9 Mar 2009)

JoeBallantin said:


> No way.. the water will only stay hot enough for 30 seconds or so, any longer than that requires a re-boil...
> 
> After 15 mins the tempature of the water would probably be <85 or 90 degrees!
> 
> I also hit the button far too much.. even if it has only taken 15 seconds to get the cup and t-bag I will also re-hit to get the water totally boiling...


 

Hmmm. I doubt your contention about the temperature drop but it will have to be subjected to scientific scrutiny using a thermometer. You may be right. Anybody out there with a thermometer ready to enlighten us on this pressing issue? 

What bemuses me though is that having boiled the water most people will then pour milk into the tea to cool it down. And milk in tea is another abomination in my book. As are tea bags. I confess though to being unable to drink it without sugar. (I too have my failings). 

We need to get back to making tea in a teapot and using a tea-cosy (anyone remember those?) to keep it warm. It would reduce our energy usage and make for a more rewarding experience. 

Regards,

Fnergg


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## LouisCribben (10 Mar 2009)

Looking at the Wikipedia article, microwaves are about 64% efficient at turning electricity into useful heat for the food/water.

An electric kettle is nearly 100% efficient, pretty much all the current consumed is converted into heat for your water. Also electric kettles are plastic usually with plastic lids which i.e. good insulators.

Also an electric kettle knows when to turn itself off when the water gets to 100 degrees, something harder to manage with a microwave.

You won't save a lot of money (if any) by boiling a cup of water in a microwave, compared to covering the element in a kettle with water.  

And as others have said, heating water in a microwave is much slower than a kettle.


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