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by philips 1479 days ago
Relatedly I found this video on electric kettles vs gas stove efficiency for heating water pretty illuminating too: https://youtu.be/_yMMTVVJI4c?t=763

The summary is that a cheap electric kettle can boil water way faster and with far less wasted energy than a stove top kettle.

5 comments

That seems pretty obvious from their construction. I don’t know anyone that uses a stove top kettle.

It’s unfortunate that in the US our electric kettles are much slower than in the U.K.

I use both. Stove top kettles are less efficient, but they have a few advantages over electric kettles. They:

- work when power is unavailable (outages, camping, etc.)

- are more or less indestructible

- don't take up counter space

I have one of those big 4L Zojirushi electric kettles that I keep plugged in for 8-10 hours a day. Sometimes I will use the stove top kettle for supplementary boiling water when people in my household are using the electric, or I don't want to start a reboil cycle or take too much at once.

Electric kettle uses the same footprint space as a stove kettle.
Are you suggesting people put their electric kettles on the stove? Or that people place their hot kettles on the counter?
When it's not on the gas stove, it has to go somewhere.
And how does that relate to counter space?
I think it can be spread by word of mouth. I've already converted several friends and family over to electric kettles when they see how useful it is for coffee, tea, even for getting water boiled for cooking.

The big question in my mind is whether the electric kettle itself is the "final form", or if I'll be proselytizing the same people in ten years to get an Asian style hot water heater/reservoir instead.

An induction-friendly stovetop kettle is a pretty great option as well, for those with induction burners. I have found it about as fast as an electric kettle, but it saves counter space, and won't have to be replaced every 1-5 years. Maybe I have just had bad luck with inexpensive electric kettles, but they kept dying on me.
A holiday rental I stayed in had a boiling water tap. It's a small improvement over a kettle, but in terms of improvement there's very little efficiency gains to be had over a hot plate directly in contact with the cooking liquid.
Once you've had one you can't go back. I don't know what the losses are from maintaining the hot water but it's the ultimate in convenience.
We use a Zwilling model at home that's very fast and simple to operate (seems strange to have to say that, but a Cuisinart model in our office is a UI and design disaster).
> with far less wasted energy

Small nit-pick: Electricity generation itself is often very lossy. In the case of fossil sources, the energy waste is just further up the chain (with solar power too, but it matters much less).

A generator powering the grid for the electric company is going to capture a far greater portion of the fossil fuel energy than the gas range in your kitchen. There will be some loss transmitting electrical power from the generator to your house, but usually less loss proportionally than than energy wasted above a gas range. As you suggest, climate-neutral renewable sources make up a tiny portion of most power grids, but that will likely change in the coming years.
This is the same reason that EVs still win on overall efficiency, even if your electrical supply is fossil fuel based. You get to take advantages of efficiency in scale.
It’s probably pretty close to a wash. A gas stove is about 40% efficient.

A good combined cycle has power plant is about 60%, transmission is about 90%, and an induction stove is about 85%. That gives a net efficiency of 46%.

So that's better if you're sourced by gas, and _way_ better if you're sourced by a renewable method? Looking at the national grid [0] in the UK, 40% of our energy came from gas, and most of the rest is renewable energy or nuclear. That significantly swings in favour of electric kettles.

[0] https://grid.iamkate.com/

Well you have to consider the margin. If you change out your gas stove, where is the extra bit of electricity going to come from? Probably gas, although they may build some more renewable if enough people switch.

A gas stove is one of the last things that should be converted, because heat is the most efficient use of fossil fuels.

In general, any conversion of heat energy to mechanical or electrical energy will have a fairly low efficiency, so switching an energy source in a way that adds such a conversion will have at best a small benefit.

On the other hand, switching from a gas to an electric car requires an extra heat->mechanical conversion step at the power plant, but it removes a heat->mechanical conversion step in the car, so in general this is a favorable trade.

You can also get a favorable trade in home heating if you replace a gas furnace with an electric heat pump, or a gas water heater with a heat pump water heater, because the heat pump can get effectively well over 100% efficiency.

> the energy waste is just further up the chain

Just because both are "lossy" that does not mean at all the losses are of comparable magnitude.

So, actual question: "You need X amount of gas in a power plant to generate enough energy for 1000 households to heat their water with induction" vs "You need Y amount for the same number of households using gas stoves". What is the ratio between X and Y? You claim it is about 1. Is it? Or much larger than 1 or much smaller than 1?

What about compared to putting a cup in a kitchen microwave?
Microwave ovens are not as good as electric kettles, but still better than gas stoves.

https://www.nytimes.com/2019/05/29/climate/nyt-climate-newsl...

"an overall efficiency [of a gas stove was] only 30.5 percent"

"The microwave was a bit better; it clocked in at about 43 percent efficiency."

"[Electric kettles] hit 70 percent efficiency."

Absolutely. Personally I do many other things besides boiling water with the stove, and I agree a kettle is a better way to do that. At least for smaller amounts of water; you’re not making pasta for 4 in the kettle.
This assumes you (everyone) live(s) in a building whose circuit breaker won’t trip when you plug in said kettle.

And it can cost a pretty penny to get a building up to this standard.

If an off the shelf kettle is popping a circuit breaker in your house (absent some other load on the circuit), there’s a reasonable chance that’s a fire waiting to happen in a faulty wiring connection somewhere.
Many cheap older apartment in Japan has poor 30A/100V power contract. Even the equipment is fine, 12A electric kettle may cause circuit braker down if they use other electronics.
Yeah, if you exceed the total load, then obviously the breaker is going to trip (that's why I added the "absent other loads" qualifier)
Old buildings aren't really the subject at hand, though[1]. Ideas about replacing standard cooking appliances are aimed at new construction and renovation. If you can afford to put in an induction range, you can surely run a wire for it.

[1] Though it must also be pointed out that older housing stock tends very strongly to be electric anyway. Gas cooktops have always been high end devices. People renting buildings in old urban neighborhoods never installed them.

I never thought of gas as being high-end. Is it because in existing construction it takes a lot more work to run pipes versus pulling a few wires through the wall?
Fast electric kettles are fast due to their high power draw and efficient design. It should be possible to find a kettle that just draws less power. It will be equally power efficient just slower and less burdensome on your breakers.