High powered kettles & vacuum cleaners plan to ban them in EU stalls

[bert]

Are you sure this isn't a spoof?

[bert]

In article , Mike Tomlinson writes

What exactly is "thirty times less" mathematically speaking?

[bert]

In article , T i m writes

Are you seriously saying you used re-boiled water to make another cup of tea? YUK! What a pleb.

[bert]

So does ours. Unfortunately the window is immediately behind the handle so difficult to see when filling. Well, it is German.

[T i m]

What it says ... a thirtieth. ;-)

Cheers, T i m

[Detritus]

...lots less :-)

[Johnny B Good]

Whilst a vacuum flask type can save some energy compared to an ordinary plastic jug kettle, it's not going to amount to very much of a saving unless the kettle is only used to boil very small amounts of water throughout the day.

It still takes the same energy to bring a mug's worth (200mL or so) to the boil regardless of whether the wattage is 600 or 3000. However, the vacuum flask design of the 600W kettle should reduce the losses to atmosphere to less than that due to the fivefold increase in time required over that of a plastic jug 3000 watt based design.

Most plastic jug kettles allow you to boil a minimum of 400ml (about 2 mugs worth) which is just enough to warm the pot and brew 1 mug's worth of tea. If you're in the habit of immediately topping back up from the

100ml mark to the 350/400 ml mark ready for your next brew in an hour or two's time, the savings of a vacuum flask type 600W kettle are unlikely to pay for the extra capital cost in such a "High Efficiency" kettle in any reasonable 'lifetime' (whether the kettle's or yours).

I've just brewed myself another mug of tea and a rough estimate of the time it took to boil about 400ml of water that had been topped up immediately after the previous boiling some three or more hours ago worked out at 90 seconds.

The water would have been a few degrees warmer than room, say 20 deg C instead of say 8 to 10 deg C straight from the tap. Obviously, the shorter the interval between top up and the next boiling, the higher the starting temperature but even after several hours, even a modest few degrees *above* ambient is a better a starting point than one some 10 degrees *below* ambient.

If I was using a 600W vacuum flask kettle to boil up 400ml of water made up from 100ml at 99 deg C from a cold tap source of 300ml at 9 deg, I reckon I'd have a starting temperature of 30 deg C as opposed to circa 20 deg C with my 3KW kettle. A rough calculation suggests I'd have had to wait an extra 5 minutes for that 400ml of water to come to the boil.

Despite the protracted heating time, the expensive vacuum flask kettle would still use less energy per such boiling. Unfortunately, the use of a

600W element (very useful to flatten a peak demand on the grid otherwise imposed by 5 million or more 3KW kettles to one fifth of the 15GW implied by 5 million kettles) imposes an undesirable time penalty of an *extra* 5 minutes for a minimal tea brewing session (the time penalty would be another two or three times greater when brewing for more than just one family member at a time in the TV Soap Viewing household).

At the moment, there's no real financial incentive for most people to invest in the extra expense of such 'Eco-Friendly' kettle technology. Indeed, from the point of view of 'efficient use' of electricity, a 3KW plastic jug kettle is better than a 1.5/1.7KW version with the added bonus of less 'hanging around time'.

If the government were to impose restrictions on maximum kettle power ratings (say a 1KW limit), then there would be an increase of interest in such high tech kettle technology by the general public which may reduce the pricing due to increased consumer demand leading to manufacturing cost savings due to mass production techniques.

The public would be forced to change their hot beverage water heating habits but this shouldn't prove to be any hardship when you can elect to fill and switch the kettle on during the previous advert break to the one you're planning on taking a hot beverage related break since very little heat will have escaped by the time of that advert break allowing a very protracted reheat to boiling point when you're ready to actually brew up a hot beverage or three.

As a strategy to trim some 10GW or so off peak demand periods, it's not a bad idea. I've seen far worse ideas proposed to make a less stable 'eco- friendly' grid retain some measure of viability. Of course, I'm ignoring the manufacturing carbon footprint implications of mass manufacturing of these high tech electric kettles (which, for all I know, may or may not be any worse than that of conventional electric kettle manufacturing).

[Mike Tomlinson]

En el artículo , bert escribió:

Dunno. You tell me.

[Mike Tomlinson]

En el artículo , Detritus escribió:

Yep. :)

[polygonum]

Ours is marked such that 2 is almost exactly 1 of our mugs.

Wish they would standardise on ml - e.g. graduations at 100 ml multiples or something like that. Means whatever you get used to on one can be transferred to another.

[T i m]

Handy timing etc ...

A mate sold his b&b in Cornwall for similar reasons (couldn't get any local tradesfolk to turn up as promised).

(After reading ahead, were the terms of that service written down and agreed anywhere OOI?)

Ah, so they had a list at least. ;-)

I guess we'd all like to think that was just one of the unlucky ones but these days ... ;-(

Cheers, T i m

[Bod]

1 30th ? ;-)

[Mike Tomlinson]

En el artículo , Bod escribió:

Works for me. 1/30 * 500 = 16.66, close enough to 15.

T'ch. Some pedants on here.

[T i m]

Yup.

True ... except you might be able to claw some of that time back if you boiled the full kettle and if you knew you were likely to be going back to it fairly regularly (working on the idea that some kettles can hold water up to 80 DegC for two hours.

Agreed.

Yup.

You could even have an app for that ... and it wouldn't 'matter' if you didn't go to it straight away.

It's not (if sacrifices have to be made for whatever reason). It's like repairing stuff rather than buying new. £20 spent on bits to repair a washing machine is the same and not having to earn a couple of hundred. ;-)

No, and especially if bought during the normal replacement cycle (as we are about to do). ;-)

Cheers, T i m

[T i m]

As mentioned previously, I don't think I have ever used the formal marking on any kettle, I just use what I learn is 'sufficient' for the demand at that time.

And for it to be any real use you would have to mark all your cups, mugs and teapots similarly. ;-)

True, you can manage what you can measure (or has the measurements printed on them). ;-)

Cheers, T i m

[T i m]

Well, you could try it (with the plastic ones). ;-)

Some friends stayed with some family who had a new / fancy / modern kitchen. She came down in the night for a cuppa and couldn't find a kettle anywhere. She ended up boiling some water in a pan ... turns out they had one of those kettle tap things. ;-)

[Johnny B Good]

Ideally of course it would, but the problem is that you can't be too

*exact* unless you're making a cup or mug of instant coffee or brewing a teabag in a mug.

If like me, you prefer to brew a teabag in a mug's worth of water in a teapot (small stainless steel one in my case) with a third of a mug's allowance to remove the chill from the pot, you can't be quite so precise. I land up heating about 3 or 4 times what I need for just what makes up a mug's worth of tea. However, this leaves some 100 to 150ml of just off the boil water which I immediately make up to some 400ml from the cold tap ready for the next brewing session in an hour or three's time so that my next boiling up session starts with water above ambient rather than some ten degrees lower.

Since the rate of heat (energy) loss is proportional to the temperature difference, it's best to dilute the heat energy of the remaining 100ml or so of almost boiling water straight away into a larger volume of water made up from the cold tap top up ready for the next boiling cycle. The energy efficiency benefit of immediate top up applies regardless of how well insulated (or not) the kettle may be. Obviously, it works better with a well insulated kettle compared to a conventional plastic jug kettle and even closer to the ideal in the case of a vacuum dewar flask based design.

Incidentally, even if you're routinely boiling only the exact amount needed leaving the kettle 'dry', it's still worth topping back up straight away to recover the residual heat from the kettle element into the fresh charge of water ready for the next boiling session.

[dennis]

Mine is marked in fractions of a litre.

[Vir Campestris]

Making Tea. ~~~~~~~~~~

Always start with freshly drawn water...

Andy

[Tim Streater]

Except that it doesn't say that. I know that's what the klod meant, in which case let him say so next time. Thirty times less energy used actually means that he's putting 29 x 500W back into the grid.