1600 W maximum on vacuum cleaners from from Sept!

[watercooled]

However, I do recall a couple of years ago, it was very difficult to track down a kettle which can boil as little as one cup.

Hence my suggestion.

Moving on, we're in the 21st century and yet we're relying on old technology to boil a cup of water.

What would new technology be exactly, and how would it improve upon our current, apparently archaic, technology? There's no getting around the simple fact that you need a given amount of energy to increase the temperature of water, which kettles are already quite efficient at. A traditional kettle on a gas stove wasted a sizeable amount of energy as heat from the flames would escape around the sides of the vessel, but with modern electric kettles, the heat source is submerged directly in the water. Although just to complicate things, when you consider the entire system efficiency, the gas kettle may not be all that bad considering inefficiencies in generating and distributing electricity vs just burning the fuel where the heat is used.

[DanceswithUnix]

I mean the dramatic rise/fall rate for any given trace at the start of the graphs, I wasn't sure what would cause such dramatic differences in consumption in the early hours of the morning, although the storage heaters you mention, combined with timers set to switch on the hour, could go some way to explaining it.

That was my take. There was a graph in there of breakdown across type of domestic appliance by hour, and storage heaters were a massive early rise that then trailed gently off as they get up to temperature and turn off. 1am sounds about right for the timer kicking in?

[DanceswithUnix]

Hence my suggestion.


What would new technology be exactly, and how would it improve upon our current, apparently archaic, technology? There's no getting around the simple fact that you need a given amount of energy to increase the temperature of water, which kettles are already quite efficient at. A traditional kettle on a gas stove wasted a sizeable amount of energy as heat from the flames would escape around the sides of the vessel, but with modern electric kettles, the heat source is submerged directly in the water.

As long as it has a flat plate at the bottom rather than a dangly element part way up then you can do a single cupful, and I have been using those for many many years. ISTR one was a "millennium edition" which dates that one

[Top_gun]

What would new technology be exactly, and how would it improve upon our current, apparently archaic, technology? There's no getting around the simple fact that you need a given amount of energy to increase the temperature of water, which kettles are already quite efficient at. A traditional kettle on a gas stove wasted a sizeable amount of energy as heat from the flames would escape around the sides of the vessel, but with modern electric kettles, the heat source is submerged directly in the water. Although just to complicate things, when you consider the entire system efficiency, the gas kettle may not be all that bad considering inefficiencies in generating and distributing electricity vs just burning the fuel where the heat is used.

Kettles using induction cooking technology perhaps, far more efficient than heating an element to produce heat.

[peterb]

Kettles using induction cooking technology perhaps, far more efficient than heating an element to produce heat.

How do you figure that out?

It takes a finite amount of energy to raise a given amount of water by a specific temperature - however that heat is applied. If the element is immersed in the water, all the heat energy will be transferred from the heating element to the water - and then to the kettle wall. Insulating the kettle will reduce that heat loss to the air, and that would increase efficiency. Some energy will be 'lost' to raising the element's temperature, but the specific heat capacity of the element is considerably less than that of the water.

Using an induction element requires heating the ferrous body of the kettle which then transfers the heat to the water. It may be as efficient, but certainly not more.

On the other hand, induction hobs are generally more efficient than normal hobs because the thermal mass of the heating element (in effect the pan) than that of the element itself, whether it is radiant or conduction. Halogen hobs are also efficient - but in both the case of halogen and induction, there is some inefficiency because of conduction to the ceramic surface.

Probably the most efficient is microwave heating, where the energy acts directly on the food to provide the heating effect - but then you need to look at the efficiency of the circuitry generating the microwave radiation.

If you really want to boil water efficiently, a glass vacuum container (not mirrored) in a microwave oven is probably your best option - but kettle or induction hob? Little or no difference.

[Zak33]

watercooled and boiling kettles

mutually exclusive I'd say!

[DanceswithUnix]

Kettles using induction cooking technology perhaps, far more efficient than heating an element to produce heat.

Erm, kettles have been available using induction technology for at least 15 years.

A coil in the base heats the plate in the bottom of the kettle.

I think all of the early hidden element kettles were like that, but I get the impression that these days they just heat the bottom of the kettle with a traditional heating element.

But as waste energy is given off as sound, light or heat, then kettles are pretty quiet and not very bright, I don't see how you can have an inefficient kettle unless it is a traditional element design that needs to be half full. Even then heating the water is efficient, it is letting half the water cool down again that is the problem.

Edit to add: Just been looking at the current Russel Hobbs range to find one like mine, but can't tell which if any are induction. Guess it isn't a sales point any more given it is old tech. Looks like you can get old school whistling hob kettles designed to go on an induction hob though. No idea what the efficiency of that would be like, but better than the old flames licking up the side ones and a very cute idea. Efficiency is probably limited by how quickly you turn if off when it starts whistling.

Another edit: OK the one in the kitchen probably uses an OPTEC element, a resistive material printed onto the heating disc at the bottom of the kettle. Would explain why induction doesn't get any hits for jug kettles, that sounds way easier to make.

[wasabi]

a microwave oven is probably your best option

For several years we've been part cooking stuff in the microwave then finishing it off in the conventional oven (or outdoor woodfired oven). Saves us a mint and quicker overall if a little more hassle.

[Top_gun]

How do you figure that out?

This was a pure speculation based on manufacturers claiming induction is the most efficient form of cooking. I must admit I haven't done any research on this matter and nor do I have any depth knowledge on induction cooking. So I'm quite happily and readily admit, on this extremely very rare event, I could be wrong. Especially as I cook with gas.

However, it doesn't alter the fact that I expect manufacturers to innovate in boiling water efficiency and perhaps EU regulations might just focus their minds a bit more.

On a personal note, it doesn't seem proper that my kettle energy uses more energy than my fridge freezer over the course of a year. I may well start to use gas to boil water for my tea as it's one of the cheapest way to boil water because gas is a primary source of energy.

[Zak33]

Boiling water via gas vs electric kettle

I look forward to your evidence and experiment on this one Topgun bud.....

Prove it and I'll do it

[Top_gun]

Boiling water via gas vs electric kettle

I look forward to your evidence and experiment on this one Topgun bud.....

Prove it and I'll do it

I don't there's any need to experiment as it has already been done here:

http://srimech.blogspot.co.uk/2008/0...ectricity.html

There are also several discussions on the net relating to gas v electric kettle. I've long known the electric kettle as the most energy efficient way of boiling water but not exactly the most cheapest method since gas is much cheaper than electricity per unit. The energy efficient electric kettle claim may not be accurate as it doesn't account for energy conversion and energy loss due to transmission from the power station.

[peterb]

:Using a primary source of energy will be more efficient than converting it to some intermediate form first.

Intuitively, burning gas to produce heat to convert to rotary motion to generate electricity is going to be less efficient than using the heat from gas directly.

The equation changes if you use solar energy to do 'useful' work. It is possible to boil water in a solar boiler, but you need to focus the suns energy using a reflector or lens system. On the other hand, you can use solar thermal panels to preheat the water so you don't use as much energy from other sources.

Solar PV is not particularly efficient at converting solar energy (nuclear!) To electricity, but as that energy is going to waste, it makes sense to harvest it and use electricity as a convenient intermediate energy source.

Going back to top_gun's assertion, one kWh of electricity costs around 14.5p, 1kWh of mains gas costs about 4.5p, so cooking on gas can be cheaper, although losses can be higher if the pan size is not chosen to match the burner size.

[Zak33]

So to do this boiling of water efficiently do I need a special pan?

I mean....do I use my smallest metal pan with lid on and just trust to the facts?

Because I always boil water for cooking....in my kettle and then into my steamer or pan which I heat with gas for a few seconds before pouring the kettle into it

I always do this and if I can save money by boiling water on the hob then I will

[Zak33]

I don't mean for making a cuppa

I'll pay for the speed and convenience of the kettle

But for full pans of water for cooking I'll move back to gas from cold tap water :-)

[CAT-THE-FIFTH]

It looks like kettles,lawn movers,hair dryers and smartphones are next:

http://www.telegraph.co.uk/news/worl...d-kettles.html

[DanceswithUnix]

I don't mean for making a cuppa

I'll pay for the speed and convenience of the kettle

But for full pans of water for cooking I'll move back to gas from cold tap water :-)

Then boil on the hob, avoid flames licking wastefully up the sides.

Had a similar argument last time I purchased a washing machine. Only really expensive ones have a hot water feed these days. The salesman gave me a load of crud about how it was more efficient to heat water in the appliance, which I pointed out was irrelevant as gas was so much cheaper that I was better off using the big tank of already hot water and wasting a bit. Was surprised no-one had picked him up on that before.

Personally I am just impatient, I boil half the water in the pan on the big 3kW gas ring, and the other half in the 3kW kettle. That halves my waiting time.