The kettle debate

Ultrasonic

Section62 said:

Ultrasonic said:

Section62 said:

maxmycardagain said:

"Only boil what you need(1 cup/2 cups) of water as needed...."

But what if...........say our kettle could hold 10 cups of water, boiled from cold at 8am, 2 cups filled then a cosy keeps the remaining 8 cups warm for 2hrs then boil (from warm) at 12 -which would be quicker from cold, at 2pm boil the 6 cups of warm water (fast), ditto at 5pm (4 cups) 8pm (2 cups)

Would need a proper road test...lol

Forget the kettle. (sell it online to raise some cash)

Put the cold water in a jug/cup and microwave it.  (take care when removing from the microwave as the water will be hot).

Experiment to find the exact number of seconds required to get a cupfull to the precise temperature required.

Trim a second or so off the time in the Summer to allow for warmer ambient temperature.

(No, I don't do this myself)

No, a kettle is better because microwaves are only around 50% efficient in turning electrical energy into microwave energy. By contrast kettles are about 100% efficient in turning electrical energy into heat.

I wasn't being entirely serious... but if we are, then I'd point out my kettle is less than 50% efficient when making my morning cup of tea.  I suspect the same applies to many other people.  (I still use it rather than using the microwave though)

I think it's important to be accurate with energy saving advice right now given how increasingly important it is becoming for many. It is absolutely tempting to think a microwave may be more efficient due to the more targeted heating but it doesn't stack up overall. I'll see if I can dig out a link I've posted before with some actual data on this later.

JohnnyB70

maxmycardagain said:

"Only boil what you need(1 cup/2 cups) of water as needed...."

But what if...........say our kettle could hold 10 cups of water, boiled from cold at 8am, 2 cups filled then a cosy keeps the remaining 8 cups warm for 2hrs then boil (from warm) at 12 -which would be quicker from cold, at 2pm boil the 6 cups of warm water (fast), ditto at 5pm (4 cups) 8pm (2 cups)

Would need a proper road test...lol

Boiling more is going to cost more. It’s still losing heat even in a cosy.

Ultrasonic

Here's the link I had in mind that compares energy usage for making coffee in various ways, including using a microwave and a kettle.

https://www.solarmill.com/blog/energyandcoffee

Xbigman

The only way boiling more than you need and storing it might make sense is if you have a time of use tariff and could boil water really cheaply and warm it up later. Even then, is it worth it remains the big question. Heating up something with cheap electric makes more sense with something that only needs to be warm. I'm thinking of Roast Potato's. I prefer them luke warm so cooking some first thing when I get up and storing in a food flask could work quite well. Stews, Soups and the like would also be OK this way. 

Well, if Agile wasn't nearly the same price all day now it would. 

Darren

Section62

Ultrasonic said:

Section62 said:

Ultrasonic said:

Section62 said:

maxmycardagain said:

"Only boil what you need(1 cup/2 cups) of water as needed...."

But what if...........say our kettle could hold 10 cups of water, boiled from cold at 8am, 2 cups filled then a cosy keeps the remaining 8 cups warm for 2hrs then boil (from warm) at 12 -which would be quicker from cold, at 2pm boil the 6 cups of warm water (fast), ditto at 5pm (4 cups) 8pm (2 cups)

Would need a proper road test...lol

Forget the kettle. (sell it online to raise some cash)

Put the cold water in a jug/cup and microwave it.  (take care when removing from the microwave as the water will be hot).

Experiment to find the exact number of seconds required to get a cupfull to the precise temperature required.

Trim a second or so off the time in the Summer to allow for warmer ambient temperature.

(No, I don't do this myself)

No, a kettle is better because microwaves are only around 50% efficient in turning electrical energy into microwave energy. By contrast kettles are about 100% efficient in turning electrical energy into heat.

I wasn't being entirely serious... but if we are, then I'd point out my kettle is less than 50% efficient when making my morning cup of tea.  I suspect the same applies to many other people.  (I still use it rather than using the microwave though)

I think it's important to be accurate with energy saving advice right now given how increasingly important it is becoming for many. It is absolutely tempting to think a microwave may be more efficient due to the more targeted heating but it doesn't stack up overall. I'll see if I can dig out a link I've posted before with some actual data on on later.

Completely agree to the BiB. That was my point.

A 'debate' of this type is problematic because there is rarely one 'right' answer to a simplistic question.  People's circumstances and needs vary.  Therefore advice needs to be tailored, and assumptions avoided.

Direct electrical heating of water is indeed close to 100% efficient.  However that is the efficiency of only part of the system.  My kettle - like a lot of people's I would suggest - has a minimum heating quantity of about 2 mugs.

Therefore using my kettle to make one cup (or mug) of tea effectively involves throwing away 50% of the work done by the kettle - slightly more than that in reality because the kettle itself has to be heated.  The system efficiency is instantly less than 50%. That's assuming I'm extra careful to fill the kettle to no more than the minimum quantity.  I'll allow for the possibility of not filling the kettle to the minimum mark, but that increases the risk of premature failure of the kettle.  An expense for replacement which would need to be accounted for in the 'Which is cheaper?' debate. (see also "sell [the kettle] online to raise some cash")

I would expect the cost of using a microwave vs a kettle to have a non-linear relationship - probably with the cost of using the microwave being cheaper for smaller quantites, and the kettle being cheaper for larger quantities, with the crossover somewhere around the kettle minimum quantity level.  (Although I could be very wrong about that)

TL;DR - no one right answer, it depends on your individual circumstances.

Also as zx81 pointed out - you have to consider the quality of the product you are willing to put up with in the name of moneysaving.  As well as the hassle factor.  Which is why I use the kettle and not the microwave to make my tea.

JohnnyB70

Not specifically the question asked, however…

We have a “super kettle”, which is a 5l kettle which is extremely well insulated. The idea is that you leave it on constantly, so you always have water ready when it’s needed.

It’s really good, and costs very little to run. They are low wattage too, so very good for camping, boats and the like.

Ultrasonic

JohnnyB70 said:

Not specifically the question asked, however…

We have a “super kettle”, which is a 5l kettle which is extremely well insulated. The idea is that you leave it on constantly, so you always have water ready when it’s needed.

It’s really good, and costs very little to run. They are low wattage too, so very good for camping, boats and the like.

From an energy saving perspective that is very wasteful though. Not really a money saving option.

JohnnyB70

Ultrasonic said:

JohnnyB70 said:

Not specifically the question asked, however…

We have a “super kettle”, which is a 5l kettle which is extremely well insulated. The idea is that you leave it on constantly, so you always have water ready when it’s needed.

It’s really good, and costs very little to run. They are low wattage too, so very good for camping, boats and the like.

From an energy saving perspective that is very wasteful though. Not really a money saving option.

It depends. It’s extremely well insulated, so only draws about 30 watts. If the alternative is heating up a lot of water to boiling then leaving the excess to cool down again then it’s possibly saving money.

Ultrasonic

Section62 said:

A 'debate' of this type is problematic because there is rarely one 'right' answer to a simplistic question. 

Did you read the actual question asked? It really is one with a single right answer as far as I'm concerned. Although possibly you were referring to kettle vs microwave. If you do then your original post wasn't nuanced but a flat out 'microwave is best' post. 

My kettle has no problem boiling a single cup of water, and I even boil less sometimes. It has a flat base rather than an exposed element and no indicated minimum fill level. I never leave it unattended when boiling and switch it off manually rather than relying of a steam related auto-switch off. 

The advice of just boiling what you needs remains correct. If someone can't do this then you can get into discussing the least-worst alternative/

wittynamegoeshere

Drinking a glass of cold water is the money saving option.

"Corporation Pop" as it used to be called.