Electric Kettle or Gas?

A_fiend_for_life

AndyR wrote: »

I've always tried to be "green" with my kettle - i.e. only putting in the water I need, but I was at my friend's today and noticed despite having an electric kettle, when he made tea, he boiled an old fashoned whistle kettle on the gas stove.

He says this is cheaper and more efficient than using an electric kettle? Is he right? Because if so I will follow his example.

You'd need to take meter readings for gas and electricity consumption for the kettles and calculate the cost and carbon emissions based on those readings.

You need to consider starting temperature, volume of water and total energy from the meter to be able to calculate the cost and energy consumption.

It seems quite possible that gas can be cheaper but not greener depending on the efficiency of the kettle but it is difficult to be certain without taking measurements.

Cost of my gas is 3.8 pence per kWh.
Cost of my electricity is 12.8 pence per kWh.

On the back of an envelope for a given volume of water:

I would need to use about 3.3 times as much kWh gas for it to be economically more expensive. ie the gas kettle would need to be as low as 30% the efficiency of the electric kettle.

Approximate (equivalent?) CO2 emissions are:

0.5 kg for electricity per kWh.
0.2 kg for gas per kWh

so the gas kettle would need to be approximately 40% the efficiency of an electric kettle or greater to be greener.

I don't know how efficient a gas kettle is but I am sure it is possible to improve them or choose a good design. eg wide copper base? clean base?

Magentasue

I've switched to kettle on gas hob (a metalkettle as my son calls it) but not because I think it'll be cheaper or greener per use. I've done it because I hardly have any worktop space in my temporary (but for at least another year) kitchen so getting kettle off helps. I also only have one double socket on one side (fridge and freezer) and one on the other.

The other thing is that family members would switch kettle on and walk away an d then reboil. Sometimes more than once. With the whistling kettle, they don't.

It also looks better! Disadvantage is that it's harder to see how much water you're filling. I've got it down to a fine art of counting to five for each cup when the tap is running. Have noticed there's always water left when others use it. Not that they were that careful with the electric kettle.

A_fiend_for_life

Here's an experiment comparing electric kettle, electric hob and gas kettle, someone's posted:

http://www.techmind.org/energy/calcs.html

No mention of a lid though nor whether a full flame was lapping up the side or underneath the pan as it should be.

grannybiker

All tea-lovers will agree that water MUST be boiling to make a decent cuppa!
At work we have an urn and if it's not quite hot enough we get a foamy scum on top! :eek:
Mountaineers also complain of not getting a decent cup as the water "Boils" at a lower temperature!

Magentasue

grannybiker wrote: »

All tea-lovers will agree that water MUST be boiling to make a decent cuppa!
At work we have an urn and if it's not quite hot enough we get a foamy scum on top! :eek:

Ah, that makes sense. We have just switched to a kettle on hob and it's fine but ... whenever OH make me tea, it's, well, as you said, foamy. Scummy even. Yet when I make it, it's normal. T'is his way. Always in a hurry. He's not letting it boil. Just as I had to train him to wait until the electric kettle switched off - not just started to steam - now, I'm going to have to insist he leaves it until it whistles properly.

Cardew

grannybiker wrote: »

Mountaineers also complain of not getting a decent cup as the water "Boils" at a lower temperature!

On the other hand submariners say it tastes great!!

Ben84

A_fiend_for_life wrote: »

Here's an experiment comparing electric kettle, electric hob and gas kettle, someone's posted:

http://www.techmind.org/energy/calcs.html

No mention of a lid though nor whether a full flame was lapping up the side or underneath the pan as it should be.

Interesting site. It seems I was slightly off if they're right, which I have no reason to doubt they are. Gas does deliver a lot more energy for less cost and CO2 emissions, but it doesn't seem to be transfering as efficiently to the kettle as I thought it would. If they're correct the efficiency is really quite low.

Anyway, it partly depends where you live. If you live somewhere which uses a lot of low carbon fuels to make electric, for example France which is largely nuclear or Brazil which has large amounts of hydroelectric, the actual figure should be much lower when using an electric kettle.

It also depends where you live on a more local scale. These figures are averages, while the electric that turns up at your house is largely from the nearest generating facility. I used to live very near the huge coal plant in Oxfordshire, so my electric then would I'm sure have had high CO2 emissions compared to the national average which is bought down by nuclear plants and natural gas plants. However, I now live on a site that has its own co-generating natural gas plant which creates our electric and the waste heat powers the central heating and makes the hot water, which results in very high efficiency.

Unfortunately as it's something you can do little about, where you live can and will have a big effect on your carbon emissions from electric used.

mech_2

The inefficiency of a gas hob in getting heat to the water vs an electric kettle is an academic issue this time of year assuming we're talking about the UK and working on the assumption that someone with a gas hob also has gas central heating. Waste heat from the hob just helps heat the house and reduces the amount of gas burnt by the heating boiler. Effectively it's 100% efficient, which may well be more efficient than the boiler, so in the winter, brewing a cup of tea with water heated on a gas hob might actually use less energy than not having a cup of tea at all!

Clearly, in the summer this isn't the case as there is no need for the central heating, so a kettle wins.

JR19

I bought a Tefal One Cup from Dixons (via Topcashback) and paid just under £45.00 about 2 months ago. It was great to start with, but the '3-second' boil soon stopped working and it now takes over 13 seconds, so it's being returned to Dixons and they will send a new one - great idea if it works properly and the water is boiling hot.

economiser

I really don't know the answer to the OP's question but it is nothing to do with the costs of electricity/gas or the time it takes to boil. It is a question of efficiency. Electricity is 100% efficient at the point of use but of course there are huge inefficiencies in getting energy from the power station to the kettle. Overall efficiency is probably only about 25%. So what is the efficiency of the naked flame burning under the kettle and what are the energy losses in gas distribution? I don't know but is suspect overall it is it better than 25% and would think therefore in overall energy terms the gas kettle is probably the more efficient.