Kettle

Khannie

So the kettle's a monster. Sure it's not on for very long each day, but when it is on it uses up a /lot/ of electricity.

We have gas, so I'm wondering if it would be much more energy efficient to get one of those whistling stovetop kettles?

My thinking:
Electric kettle = water boiled, turbine moved, electrons pushed, heat generated, water boiled.

Stovetop kettle: water boiled.

Vagabondo

Well, Khannie
You are thinking just right, and it's good you have a choice of gas and electricity.
In my oppinion you have to choose the cheaper solution for your household. You can fill the kettle only with nesessary amount of water and try to measure the costs of boiling it different ways. I can presume that gas delivery and electricity generating and delivery to our houses have both a huge carbon footprint. That's why I would go for the cheaper option and introduce a flask once again for myself :-)

Macha

Although....with the kettle, the element is emersed in the water and most, if not all, of the energy goes straight into the water. With the stove, you're heating the water indirectly though the bottom of the pan/kettle and it's only coming from one direction.

Plus if you're interested in the eco side of things and if you're with Airtricity, the kettle would definitely be the better option.

Khannie

Ah yes but for the electric kettle, the energy has been converted several times, resulting in a big loss.

I think we may have to move this one to the physics forum.

c-note

using electricity to heat anything is a pretty poor use of electricty,
electricity is very high quality energy, i.e. its very versatile (think of the multitude of uses for it) whereas gas is only really used domestically for heat.
my opinion is that you'd be better using the gas if you can live without the convenience of the lectric kettle.

robtri

Khannie wrote: »

S

My thinking:
Electric kettle = water boiled, turbine moved, electrons pushed, heat generated, water boiled.

Stovetop kettle: water boiled.

Your thinking on this already is pushing towards gas....

but surely you forget, gas = gas drilled, gas piped using pumps, gas bottled using pumps or pushed via pipe into your house using pumps, gas ignited and burn to procduce heat to heat kettle....
a lot of ancillary devices like electricity used to get gas to your door as well.....


Anyway, back to point, to determine which is more efficient, if I am thinking about this right, the amount of heat needed to heat the water is constant, if you are using electricity or gas,
to heat one litre of water one degree is 4.187KJ, therefore to raise water temp say 80 degrees(i.e to boil water for a cup of tea) would require 334.96KJ which converts to 0.09KWH of energy needed.
Electricity is 17 cents per KWh and Gas is 3.7cents per KWH

gas is cheaper to heat the water....

I will leave you to figure out which is better for the enviroment.....

oscarBravo

I got one of those instant-hot-water jobbies, which means I only boil* the amount of water I actually need at any given time.


* It heats the water to 95 degrees - not quite boiling, but hot enough to make a decent cup of tea.

Khannie

oscarBravo wrote: »

I got one of those instant-hot-water jobbies

What's that now? Like an electric shower kind of thing?

Saruman

Yup, you can get them in Argos. Water goes in cold and comes out hot instantly. Probably not as hot as a boiled kettle but perfect for a cup of tea or coffee.

oscarBravo

http://www.quickcup.co.uk/

Saruman

They seem to be around the €80 mark. Argos has a breville one too (see alternatives).
http://www.argos.ie/webapp/wcs/stores/servlet/Search?storeId=30001&langId=-1&q=QUICK+CUP&pp=20&c_1=1|cat_12160029|Small+kitchen+appliances|12160109

They are filtered too although im not sure of the point of that since the water is boiled, well its hot anyway.

Vagabondo

oscarBravo wrote: »

I got one of those instant-hot-water jobbies, which means I only boil* the amount of water I actually need at any given time.


* It heats the water to 95 degrees - not quite boiling, but hot enough to make a decent cup of tea.

Would that be more energy efficient?
Is the water filtered before boiling?

Khannie

A fine looking device. I make quite a bit of coffee for myself and the mrs. so I'm not sure it'd be suitable for me (I boil just shy of 1L when I'm making a large cafetiere).

oscarBravo

I'd say it's a huge improvement for my usage pattern: I regularly make a single cup of tea (work at home most of the time), and I'd often boil the kettle and forget to make the tea for a bit, then boil it again later...

It has its downsides - not the quietest gadget as it pumps the water through (although I've had louder kettles). I've used it to fill my Eva Solo teapot, which is broadly similar in size to a cafetiere.

quentingargan

OK. Going nerdy here. ESB uses gas to produce about 60% of our electricity. They burn the gas to heat water to produce steam which drives a turbine which makes electricity (yawn). Of the energy in the gas, only 40% gets turned into electricity, and they manage to lose some of that in the grid on its way to your house.

So it's not very efficient use of electricity to again use it to heat water.

But if you put a heavy kettle on the gas with only one cup of water in it, then you are heating up a lot of steel and the surrounding air etc.

My hunch is that for one cup, electric is fine. For a crowd, better to use the whistling one on a gas stove.

Our house runs on a wind turbine and battery system, so hair driers and electric kettles are usually out of the question. We use gas, and fill it from the hot tap, which is supplied by a solar panel during the summer. Not sure if the coffee is all that good for me though...

maniac101

It should be said that electric kettles, particularly the cheaper versions, are very energy-efficient devices in themselves. Even taking the inefficiency with which we generate electricity into account (Quentin's turbine excepted!), I believe that a cheap electric kettle will easily beat the stove kettle boiled on a gas hob when it comes to heating a litre of water.

• Unlike a stove kettle, an electric kettle switches itself off automatically when the required temperature is reached. A stove kettle will boil on until someone removes it from the stove.
• A cheap electric kettle will be made of plastic, which is a good insulator, so it reduces the loss of heat to the surrounding air. Stove kettles, and all metal kettles, are inherently inefficient because of their poor insulation properties. An plastic electric kettle will not need to be reboiled if the water is unused for a couple of minutes.
  
• In a cheap electric kettle, energy is transferred directly to the water through the element, as there's nowhere else for the energy to go. With the stove kettle the heat must be transferred through the metal base of the kettle. With stove kettles, most of the heat energy goes into the atmosphere, not into the water.
  
• Electric kettles generally boil quicker, so the time they spend losing heat to the surrounding air is shorter.

Either way, for most of us, the biggest energy saving can be achieved simply by boiling only the exact amount of water needed, and boiling it only when we need it.

lostexpectation

me ma always tells me teabags dont' work without them having boiled water on them