Making a cup to tea - whats cheaper gas or electric kettle?
#32
From ScoTTyB's tests I'd say the efficiency difference between electric kettle and gas hob is much larger than the 0.9 and 0.7 used by warrenm2.
If the kettle used 220 kJ and the gas hob used 720 then the gas hob is about 3.3 times worse, so if the kettle stays at a nominal 0.9 the gas hob ends up at 0.27.
Then warrenm2's total for gas is 526kJ instead of 203kJ.
Therefore price to boil a cuppa on
gas = 526*453/3600 = 0·66p
leccy =158.12*66/3600 = 0·555p
In other words, we can't tell without an exact measurement of the amount of gas and elactricity used
If the kettle used 220 kJ and the gas hob used 720 then the gas hob is about 3.3 times worse, so if the kettle stays at a nominal 0.9 the gas hob ends up at 0.27.
Then warrenm2's total for gas is 526kJ instead of 203kJ.
Therefore price to boil a cuppa on
gas = 526*453/3600 = 0·66p
leccy =158.12*66/3600 = 0·555p
In other words, we can't tell without an exact measurement of the amount of gas and elactricity used
#33
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mmm I'd be REALLY surprised at that transfer efficiency! Infact looking around the web I found eBay.co.uk Guides - Buying a Hob Electric or Gas which gives a restated efficiency of gas hob as 0.55, giving an energy requirement of 258.5kJ and making my revised gas cost at 0.248p
(my B.Eng coming in useful at last! )
(my B.Eng coming in useful at last! )
#34
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And to all the other people commenting on different ways of making/heating the cuppa, you are forgetting your GCSE physics. Sure there are some differences in the efficiencies of these devices but the fact remains, that the amount of energy required to heat a set amount of water, a set amount of temperature always requires the same amount of energy. The differences in efficiency are small compared to the cost differential between electricity and gas
#35
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Don't forget this is a Subaru site.
Drive home at 100mph. Spray water onto front discs and exhaust. Catch hot water as it drips off. Virtually free hot water, (although the flavour is an acquired taste )
Drive home at 100mph. Spray water onto front discs and exhaust. Catch hot water as it drips off. Virtually free hot water, (although the flavour is an acquired taste )
#36
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You're right that the same amount of energy has to be transferred into the water in each case, but the amount of energy that doesn't end up in the water is considerable. If you don't believe me, make yourself a nice cup of tea, then before it's had chance to cool down, firmly grasp the kettle element or gas ring. Report back when the smell of frying bacon has subsided
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Andy,
Check the link that I posted, it gives the efficiencies. the difference between 0.55 and 0.9 is a factor of 1.6. The difference between gas and leccy prices are 3.453 to 12.66, a factor of 3.7, hence the price is the largest factor - easily outweighing the efficiency issues
Check the link that I posted, it gives the efficiencies. the difference between 0.55 and 0.9 is a factor of 1.6. The difference between gas and leccy prices are 3.453 to 12.66, a factor of 3.7, hence the price is the largest factor - easily outweighing the efficiency issues
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The calculations are too simple. You gotta first establish the boiling point of the water which will vary with altitude and the weather. Also you have to allow for energy which escapes as water vapour and steam before your kettle gets up to the boiling point. I suspect the boiling point of the water is going to vary depending on the dissolved mineral content too. I expect there is a whole load of other real world stuff to consider in addition.
#43
Anyone just considered drinking tap water instead ?
I am getting tight now things are getting more expensive, like using the showers at work after cycling in, its great, save the petrol, the water and the electricity !
I am so hoping that the British public embrace the energy saving and thrift mentality in conjunction with companies providing more efficient appliances, vehicles and renewable energy, then at some point in the future we are less reliant on Fossil fuels, to the point where the price plummets and they cant give it away, might take a long time but you never know.
I am getting tight now things are getting more expensive, like using the showers at work after cycling in, its great, save the petrol, the water and the electricity !
I am so hoping that the British public embrace the energy saving and thrift mentality in conjunction with companies providing more efficient appliances, vehicles and renewable energy, then at some point in the future we are less reliant on Fossil fuels, to the point where the price plummets and they cant give it away, might take a long time but you never know.
#44
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Speedking, you need BTC spec water cooled calipers, once flushed thro' will make a fine cup of coffee !
LOL
DunxC
P.S. Energy efficient my RS, my new washer has a cold feed only....
LOL
DunxC
P.S. Energy efficient my RS, my new washer has a cold feed only....
#46
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Fuel source-->process fuel--tranport fuel-->Burn fuel-->boil water-->create steam-->drive turbines->step up tranformer-->national grid-->step down transformers-->home-->kettle-->water.
Its just one huge circle: Boiling water to boil water somewhere else!
Gas reserve-->Process-->pressurise-->network-->storage-->network-->house-->hob-->kettle-->water
At least that is a little more direct.
Last edited by Shark Man; 18 July 2008 at 10:12 PM.
#49
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You all need to but one of THESE. They cost about Ł800 to buy but you soon make back the costs on the energy you save. Instant boiling water and you only use what you need i.e you want a cup of tea, you just fill your cup directly from the tap!
Plus we sell them so if anyone wants one, come to me
Plus we sell them so if anyone wants one, come to me
#50
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You all need to but one of THESE. They cost about Ł800 to buy but you soon make back the costs on the energy you save. Instant boiling water and you only use what you need i.e you want a cup of tea, you just fill your cup directly from the tap!
Plus we sell them so if anyone wants one, come to me
Plus we sell them so if anyone wants one, come to me
#51
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The fact that people often boil more water than they use and has been said on this thread boil it twice due to forgetting, they significantly save energy. Why waste the energy on boiling a litre of water to fill one cup of tea? The fact is they are proven to save energy and money
#52
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The fact that people often boil more water than they use and has been said on this thread boil it twice due to forgetting, they significantly save energy. Why waste the energy on boiling a litre of water to fill one cup of tea? The fact is they are proven to save energy and money
#53
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When I worked it out a while ago, boiling exactly enough water for a cuppa cost about 1p in electricity. Assuming the actual cost were 2p - hopelessly wasteful, really - your Ł800 gadget would have to make 80,000 cups to pay for itself. At 3 cups a day that's payback in a mere 73 years
Might make more sense on a building site!
[edit]: just checked the site, apparently it uses a continuous 10W, or 3p a day, whether it's used or not - so in fact at 3 cups a day it'll pay for itself... never!
Might make more sense on a building site!
[edit]: just checked the site, apparently it uses a continuous 10W, or 3p a day, whether it's used or not - so in fact at 3 cups a day it'll pay for itself... never!
Last edited by AndyC_772; 21 July 2008 at 04:52 PM.
#54
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isnt' electricity cheaper at night on some tarrifs??
make all you tea between 11pm and 4am. sorted !!!
some great calculations on here btw. !!
make all you tea between 11pm and 4am. sorted !!!
some great calculations on here btw. !!
#56
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I do that when out camping: thermos of boiling water. And reheat it on the stove when I want a proper hot brew.
Couple times I've had a few peeps who hadn't gone with me before admiring my stove at how quick it boiled water (they didn't see me fill the kettle from teh thermos).
Couple times I've had a few peeps who hadn't gone with me before admiring my stove at how quick it boiled water (they didn't see me fill the kettle from teh thermos).
#57
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#58
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On another note, look at the posts from GAV
he hit 5000 posts and then stopped posting last year?
how random
Gav
finally 5000 posts...
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finally 5000 posts...
Trader Score: (0)
Join Date: Sep 2002
Location: In the sport section...
Posts: 5,001
he hit 5000 posts and then stopped posting last year?
how random