Cost of boiling water in kettle vs gas hob

haveabreak

Hello,

Give the recent increase in gas prices I wanted to find out which is now the cheaper method to boil 500ml of water, gas hob vs electric kettle?

Does anyone know how can I do calculation or a calculator website? I can get the electric and gas tarrif from my supplier. And find the output for my kettle and gas hob I suppose - but OK to go with assumptions.

Thanks

Gerry1

With everything else switched off, just read the relevant meter before and after, then do the sums.

Might be more accurate if you use a full kettle (or several).  If your electricity meter only shows whole kWhs, just count the red flashes or disk revolutions.

https://www.businessenergy.com/business-gas/gas-bill-calculator/  (Scroll down)

Ultrasonic

I would (and do) just use an electric kettle but always only 'fill' the kettle with exactly the amount of water that I want, using a measuring jug.

If you really want to do a comparison then you can do this for yourself. For the gas hob test do it at a time when you aren't using gas for anything else, read your gas meter before and after boiling the water and this will tell you how much gas was used. Then convert this first to kWh and then cost. For the electric kettle you'll probably find it's power on the base. If so then you can use this combined with timing how long it takes to boil the water to calculate the kWh used, and thereby the cost. 

The above won't accout to the heating benefit of energy in each case that doens't actually go towards heating the water.

Rodders53

https://forums.moneysavingexpert.com/discussion/4123575/cheapest-way-to-boil-water is a nearly 10 year old thread on the same question.  (post by victor2)
You'd have to alter the price per kWh of gas and electric to bring up to date and assume that the 'experiment' made would be the same for you.

https://checkappliance.co.uk/which-is-more-energy-efficient-electric-kettle-or-stove-top/ has another view - again correct the own prices for gas and electric they've used.

Google will find you other places where the same Q is asked and answered.

In the grand scheme of energy consumption kettle water boiling is 'in the noise' imho.

Additionally the same Q is discussed recently here https://forums.moneysavingexpert.com/discussion/6300368/economic-kettle

merchcon55

Back of the napkin calculation - say a 3000W electric kettle takes 1 minute to boil 1 cup of water for a coffee.

3000W/60 minutes = 50 Watts used for 1 cup

50 Watts x 20 cups = 1000Watts =1 KW

Say 1KW electricity = 22p = 1.1p to heat the water for a cup of coffee.

As stated above: In the grand scheme of energy consumption kettle water boiling is 'in the noise' imho.

Ultrasonic

merchcon55 said:

Back of the napkin calculation - say a 3000W electric kettle takes 1 minute to boil 1 cup of water for a coffee.

3000W/60 minutes = 50 Wh used for 1 cup

50 Wh x 20 cups = 1000Wh = 1 kWh

Say 1kWh electricity = 22p = 1.1p to heat the water for a cup of coffee.

As stated above: In the grand scheme of energy consumption kettle water boiling is 'in the noise' imho.

To avoid confusion you meant Wh and kWh at various points in your original post - I've edited the quote above with this in mind. Watts is a measure of power (energy per unit time), whereas Wh is a measure of energy. I know this will sound pedantic but it's an important distinction, and one worth making clear when trying to help people understand energy use.

Your example is very much still helpful though  . 

merchcon55

No problem at all - you are 100% correct.

Sea_Shell

I recently did this "not so scientific" experiment if it helps.   From the PoV of cooking pasta, and which was best for getting the pot boiling, before adding the pasta (obviously you'd then continue to cook it on the hob)



To try and answer the question of which is cheaper (for me) to boil 1 litre of water, electric kettle or pan on a gas hob.

1 litre in the kettle (3kw), took 2 mins, so used 100w.   0.1 of a kw.   Our tariff* is 17.48pkwh, so by that method it cost 1.75p

Now we are able to monitor the gas used (as no pilot light now** to affect the usage), I boiled 1 litre of water in one of our medium (Tefal style) pans on the medium ring, which took 5.5 mins and used 0.3kw, so 3 times as much in energy terms.

However, the price of gas is (currently) much cheaper, only 3.2pkwh, so would have only cost just under 1p.   

So if you want to "save the planet" use a kettle.
If you want to "save money" use a gas hob.

* tariff is inc VAT.
** Recently had a new system boiler fitted.


So there you have it.    A "real world" but loosely scientific experiment.

Which means i'll continue to just boil in the pan if i'm cooking pasta etc. but I'm not going to be faffing around with pans if I want a cup of tea!!!

Ultrasonic

Sea_Shell said:

I recently did this "not so scientific" experiment if it helps.   From the PoV of cooking pasta, and which was best for getting the pot boiling, before adding the pasta (obviously you'd then continue to cook it on the hob)



To try and answer the question of which is cheaper (for me) to boil 1 litre of water, electric kettle or pan on a gas hob.

1 litre in the kettle (3kw), took 2 mins, so used 100w.   0.1 of a kw.   Our tariff* is 17.48pkwh, so by that method it cost 1.75p

Now we are able to monitor the gas used (as no pilot light now** to affect the usage), I boiled 1 litre of water in one of our medium (Tefal style) pans on the medium ring, which took 5.5 mins and used 0.3kw, so 3 times as much in energy terms.

However, the price of gas is (currently) much cheaper, only 3.2pkwh, so would have only cost just under 1p.   

So if you want to "save the planet" use a kettle.
If you want to "save money" use a gas hob.

* tariff is inc VAT.
** Recently had a new system boiler fitted.


So there you have it.    A "real world" but loosely scientific experiment.

Which means i'll continue to just boil in the pan if i'm cooking pasta etc. but I'm not going to be faffing around with pans if I want a cup of tea!!!

Another point in favour of gas in the above example is that it has also heated up the saucepan. When you pour boiling water from a kettle into a cold pan it is immediately cooled down by the cold pan, and more gas has to be used to heat up the pan and get the water back to boiling.

The key advantage of the electric kettle is that it is faster. 

Grizzlebeard

Years ago, maybe 4 - 5, I did some experiments on minimizing energy use and amazingly found I still have the little scrap of paper with my penciled notes.

1 cup of coffee. (2017? prices)
Gas = 0.00225 ft3 =£0.361p
Elec = 0.925kWh = £0.4211p

This was not the cost of boiling a cup of water, but making the most energy efficient mug of hot white coffee I could.

For gas I counted the little wheel turny-thing, for Electricity I calculated seconds switched on @ 3kW.

I use 3/4 cupful, allowing space for milk and a tortuous routine to retrieve waste energy for the next cup that confounds my occasional visitors.

(Today I use gas. Not because of the cost, but since renewable electricity never reaches 100% and any excess demand is supplied from gas it's actually greener to use the gas directly rather turn it into electrons first.)


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Important edit

Thinking about my post (over a cup of coffee) I've realized my final conclusion is a load of tosh when it comes to making coffee. If my gas was four times cheaper than my leccy per kWh, and the cuppa costs worked out about the same, then my gas kettle must have lost three times more heat to the environment than the electric kettle (give or take).

Although my "Gas is more efficient when not turned into electrons first" statement is true in principal (I think) it's not necessarily true in practice.

Petriix

Obviously there's a significant additional factor which is that the extra energy lost when boiling the gas kettle is still potentially useful in the colder months and will directly save you having to run the heating that little bit more.

In my case this is compounded by having solar panels. So we run the electric kettle when it's sun and the gas kettle when it's not.