# Cheaper to make coffee with Gas Hob or Electric Kettle ?



## bullworth (19 Jan 2012)

A question I am pondering. Given 2 equal quantities of water. One is poured into an empty electric kettle which is then boiled. The other is put into a small saucepan with lid which is also boiled. Which costs less to boil in order to make  a coffee  ?


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## extopia (19 Jan 2012)

The amount of energy required is the same in both cases. So it depends purely on the relative efficiency and relative costs of the electricity and gas supply. I'd say the cost difference is negligable, at least to the extent that it's not worth worrying about. But I am ready to be reprimanded.


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## callybags (19 Jan 2012)

I carry out this experiment under strict laboratory conditions every Saturday morning.

I have en electric hob which has an element that looks about the same size as that in the kettle.

I put on two eggs to boil.

Simultaneously I fill enough water into the kettle ( about the same as for the eggs) and switch it on.

I always seem to have my coffee half drunk before the eggs come to the boil.

Hope this helps


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## horusd (19 Jan 2012)

Lol, callybags. I would guess the kettle is quicker & cheaper as heat source is directly in contact with the water.


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## ClubMan (19 Jan 2012)

callybags said:


> I carry out this experiment under strict laboratory conditions every Saturday morning.
> 
> I have en electric hob which has an element that looks about the same size as that in the kettle.
> 
> ...


Ergo you should boil your eggs in the kettle and then use the leftover water to make your coffee. QED.


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## Sandals (19 Jan 2012)

Boil the eggs in the kettle and then make ur coffee and save the rest of the water in a thermal flask for use during the day!


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## Leo (19 Jan 2012)

extopia said:


> The amount of energy required is the same in both cases. So it depends purely on the relative efficiency and relative costs of the electricity and gas supply. I'd say the cost difference is negligable, at least to the extent that it's not worth worrying about. But I am ready to be reprimanded.


 
Sorry to jump in with the reprimand , but the unit cost of electricity is more expensive than that of gas. Looks like prices are generally around 18c a unit for electricity versus 5c for gas. 

Kettles are highly (~90%) efficient, so the majority of the energy consumed is transferred to the water. A pot on a gas hob is going to be less efficient. This you can tell yourself by the heat given off around the pot. This guy went perhaps a little too far working this out, but found that it took almost three times as much energy to boil the same amount of water in a pan over a gas hob.

So at those rates, yes, you'll use more energy using gas, but it's cheaper energy, and likely to be very close, but electricity will just edge it. 

However, if it's a little chilly and your kitchen could do with being a little warmer, use the gas, as the heat lost through inefficiencies of heating a pot of water will be heating the room!
Leo


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## bullworth (22 Jan 2012)

Thats a fantastic lesson in how to be stingy.. I mean prudent 

Does the lower unit cost of gas mean that gas heating is  the cheapest way to heat ones house or at least cheaper than electricity ?


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## Leo (23 Jan 2012)

Yes, gas is a much cheaper source of space heating. The SEAI domestic fuel cost [broken link removed] will give you a good guide.
Leo


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## Shane007 (23 Jan 2012)

Gas hob will have approx 1kW output hob ring whilst kettle will be 3kW. Therefore it will take over three times longer for the gas to boil the water, taking into account efficiency of each.

Cost will also depend on whether gas is natural gas, butane gas or propane gas. Each varies in cost significantly.


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## huskerdu (24 Jan 2012)

Here is some guesstimates  
According to the esb energy calculator

2.5kW electric kettle costs 32c to run for 1 hour. 
A small ring on a gas cooker costs 7.4c to run for 1 hour. 

(These prices are based on the ESB discount rates)

If we estimate that the kettle will take 5 minute and the gas hob 15 minutes to boil the water ( complete guess), then we have

electric kettle 2.6c
gas hob          1.85c

There numbers could be out by 100%, but it does show that the numbers are so small that it doesn't really matter.


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## Shane007 (24 Jan 2012)

Those figures do not sound off the mark. If you wait 15 minutes for the kettle to be boiled you will probably have gone off the idea of a cuppa and wasted the 15 minutes of gas usage anyhow, lol. Probably better to stick to the ol' elecky on this one.


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## Sue Ellen (24 Jan 2012)

Better idea.  Make a nice of milky coffee in the microwave, probably cheaper, nicer and definitely fattening


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## Shane007 (24 Jan 2012)

Now there's an idea. Back in ....


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## bullworth (25 Jan 2012)

how does microwaving a cup of hot water compare to the above ? I usually find microwaving for 2 minutes is enough to make even a large mug hot


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## huskerdu (26 Jan 2012)

bullworth said:


> how does microwaving a cup of hot water compare to the above ? I usually find microwaving for 2 minutes is enough to make even a large mug hot




Why dont you use the esb energy calculator to find out how much it costs to run a microwave for 2 minutes and compare ?


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