Do microwaves have some magic efficiency trick that lets them produce heat faster from the same exact energy? Like, how do they manage to be more than 100% efficient?
Microwave magnetron efficiency is around 65%. Since a kettle turns electricity directly into heat, it’s basically 100% efficient.
A caveat is that microwaves will heat water directly and won’t lose as much to its surroundings. This is similar to why induction stoves are more efficient; they’re less efficient on paper than direct electric heating or burning gas, but they heat the thing you want in a more direct way.
Even so, a microwave isn’t great for this task. If you’re short on space and don’t want even a small travel kettle, I can see why you’d take this option. Otherwise, no.
Our electricity is 120v here in the US, so kettles take forever
US outlet is 120V@20A = 2.4kW UK outlet is 230V@13A = 3.0kW
It’s a 15% difference based on possible power draw.
Anecdotally the stove will still take many times longer. Even compared to induction my kettle is faster.
My guess is that in the UK/EU it’s not common to have powerful microwaves?
Most residential outlets in the US are going to be a 15A limit. You also have to reduce that by 20% for a continuous draw.
UK might be able to get away with the full usage because their plugs are designed to have a fuse built in. Not entirely sure on that, though.
That said, kettles are still a better option most of the time. Technology Connections has real world tests of this.
Yeah, makes sense. The statement that “half the voltage is half the power” is what started me from another reply. Then this was the next one.
For extremely small values of ‘forever’
Do microwaves have some magic efficiency trick that lets them produce heat faster from the same exact energy? Like, how do they manage to be more than 100% efficient?
They don’t, kettles just aren’t that much more efficient at 120v. Like a kettle will still be faster, just not by enough for people to care.
Microwaves are designed to heat water molecules. https://en.m.wikipedia.org/wiki/Microwave_oven
They are, in fact, designed to resuscitate frozen hamsters.
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Microwave magnetron efficiency is around 65%. Since a kettle turns electricity directly into heat, it’s basically 100% efficient.
A caveat is that microwaves will heat water directly and won’t lose as much to its surroundings. This is similar to why induction stoves are more efficient; they’re less efficient on paper than direct electric heating or burning gas, but they heat the thing you want in a more direct way.
Even so, a microwave isn’t great for this task. If you’re short on space and don’t want even a small travel kettle, I can see why you’d take this option. Otherwise, no.