US water softeners are usually only on the hot pipe. They tend to add sodium to the water, and it's not recommended to make it your primary drinking water source.
frezik
Southern US is the best place for developing new methods to kill yourself in delightful ways.
You get 3-phase in the US if you live in a large apartment complex. Especially if it has an elevator. Since this combines to get 208V, the math works out to making your 240V stove only 75% of what it should be.
For residential use, split phase is fine. We just run the two legs to get 240V on the specific things that need it. That's generally electric stoves, water heaters, AC unit, electric dryer, and more recently, EV chargers. 3-phase is great when you're driving something that spins with a high draw, and of those, only the AC unit does that (electric dryers spend most of their electricity heating, not spinning).
As a combo tea/coffee drink, it tastes horrible. Nobody wants tea flavored coffee or coffee flavored tea. Although you usually don't get tea flavored coffee in those hotel drip makers, but only because the grounds they use are shit tier quality and taste too burnt to even get tea flavors.
Have to drop the US number by 20% for continuous loads like a kettle would be.
That said, US homes built in the last 40 years or so tend to have a lot of separate circuits in the kitchen. My house has one for the fridge, one for the disposal, one for the dishwasher, one for the lights that's shared with lights in adjacent areas, stove has its own 240V outlet, and then one for all the other plugs. If I ran the microwave and a kettle and a mixer all at once, I'd probably still trip it, but that's a lot of multitasking going on.
Zojirushi. They last. Since it's BIFL, I don't see the extra cost as a big problem. That's what you deal with when you BIFL.
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.
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.
We have a Zojirushi. 120V does limit it somewhat, but it's fine.
The water in our area of country is also hard as shit. We have undersink RO now, but before then, mineral buildup in the kettle was bad. Crusted like concrete if we didn't stay on top of it.
Along those same lines, they didn't put parking lots in Sim City. They tried, but it completely fucked everything.
A good reminder that the system was already broken before Trump got here.
Besides all the points everyone else has mentioned:
Always be skeptical anytime anyone uses an argument of this form. There are tradeoffs for everything, but this phrasing only serves to stop people from weighing them fairly.
Oh, and the above quote comes from the co-sponser of the bill, who is a Democrat. Just in case you thought this was a Republican problem.