Kettle on Gas vs Electric Kettle

Spies

Side note, you save 3 seconds by boiling room temperature water vs out the tap. 

jrawle

Some other thoughts that came to mind this evening (just for fun, you understand, not because I'm arguing with what anyone has said!) Do people run the extract hood when they boil water on the gas hob? I guess a kettle also produces steam, but burning gas produces additional water vapour. (I never use my hob without the fan running, but then I'm usually doing something more than making tea.)

My final comment is, if it takes five minutes to boil water on the gas hob, does that end up wasting an extra four minutes of your time? How much is your time worth? Money isn't everything. Is it worth the extra trouble of using the gas hob to save a small amount of money?

Spies

I personally don't feel the extra humidity generated by boiling water on a stove needs dealing with, depends how long you leave it whistling I guess! 

lohr500

Captainkirk54 said:

Anybody have an electric toothbrush and try to charge in a bathroom shaver socket. It does not fully charge and the transformer in the socket overheats. The toothbrush sits on the charger but there are no contacts because its in a bathroom which would be unsafe. It charges by induction and the magnetic induction current overloads the basic shaver socket - special high power saver sockets for charging toothbrushes in the  bathroom are available. They have both  shaver and toothbrush logos on them

We must be lucky then as we have been charging our electric toothbrushes for well over 10 years on the same standard shaver socket without any signs of overheating or failure. The toothbrushes always show a full charge after sitting on the induction bases for a while. Perhaps the older sockets were of a better quality in the 1st place.

Sea_Shell

jrawle said:

Some other thoughts that came to mind this evening (just for fun, you understand, not because I'm arguing with what anyone has said!) Do people run the extract hood when they boil water on the gas hob? I guess a kettle also produces steam, but burning gas produces additional water vapour. (I never use my hob without the fan running, but then I'm usually doing something more than making tea.)

My final comment is, if it takes five minutes to boil water on the gas hob, does that end up wasting an extra four minutes of your time? How much is your time worth? Money isn't everything. Is it worth the extra trouble of using the gas hob to save a small amount of money?

Personally, I'm sticking with the electric kettle for now, as it's quick and easy.  Yes, it's more expensive, and I'm lucky in that I don't have to watch every penny.

Either way it's still vastly cheaper than buying a take-away hot drink!!     So, I'm sure there are other monetary cut backs to lower hanging fruit that can be made before we all end up boiling water over an open fire!!

pensioner2

A KW of electricity costs 5x a KW of gas [mainly because of going green and paying for so called smart meters].  I can remember when a KW of electricity  cost little more than 2x a KW of gas.

wild666

I fill a 1.1 litre flask with water and two tea bags that gets me through most of the day. The cup on the flask makes just over 4 cups of tea but the downside is that by the time I get to the last cup it's only lukewarm and need drinking quickly.  

Grumpy_chap

jrawle said:

Spies said:

The half hour reading on my Gas smart meter has updated so we have results.

These workings are based on unit prices of 20p/kWh for Electricity and 4p/kWh for Gas.

500ml of cold water, enough for 2 cups of tea took 5 minutes to boil on the gas stove, that was using a small milk pan with a lid over the top, this used 0.17kWh of gas, costing 0.68p

The same test using an electric kettle, which ran at ~2800w for 1 minute 24 seconds, used 0.0715kWh of electricity at a cost of 1.43p

Looking at the figures again, if the electricity usage is accurate, that suggests the electric kettle is only 75% efficient.

The theoretical value for a 100% efficient kettle:

Energy used = 0.5 x 4200 x 90 = 189 kJ = 0.0525 kWh

(mass of water = 0.5 kg, specific heat capacity of water = 4200 J/kg/K, temperature difference 90K assuming water starts at 10°C, makes little difference if you use 100)

That means the hob is only 30% efficient. Of course, this makes no difference to this discussion as the relative efficiencies are the same. I'm just commenting for interest's sake as many people, including myself, often claim that electric water heating is nearly 100% efficient.

Thank you for doing this, but there is a difference in the efficiency of the kettle and the efficiency of the electric heating.

The electric heating is nearly 100% efficient.

Once the electric heating is incorporated into the overall process (electric kettle) the process introduces losses resulting in the electric kettle having efficiency of 75% based upon the calculations above.  The losses are any of the energy that does not end up in the water boiled - these include increasing the temperature of the body of the kettle, losses to environment, over-run.

Effician

Sea_Shell said:

jrawle said:

Some other thoughts that came to mind this evening (just for fun, you understand, not because I'm arguing with what anyone has said!) Do people run the extract hood when they boil water on the gas hob? I guess a kettle also produces steam, but burning gas produces additional water vapour. (I never use my hob without the fan running, but then I'm usually doing something more than making tea.)

My final comment is, if it takes five minutes to boil water on the gas hob, does that end up wasting an extra four minutes of your time? How much is your time worth? Money isn't everything. Is it worth the extra trouble of using the gas hob to save a small amount of money?

 before we all end up boiling water over an open fire!!

I almost resemble that remark

We boil our kettle on the log burner not a very efficient way of getting hot water though, the bonus is the house is nice & warm..

Petriix

Actually, burning gas at home in order to save electricity drawn from the grid is likely 'greener' (causes less CO2 emissions) in winter. This is because almost all immediate additional demand for electricity is met by burning gas.

At a best estimate, a gas power station has a round trip efficiency of 60%. The losses from a gas boiler are much lower at around 80-90% efficiency.

While a gas stove top kettle might only be 40% efficient in terms of heat transferred to water, all of that heat is retained in the house so there will be a corresponding drop in the gas used by the boiler for heating.

In winter at least, we can consider 100% of the energy used by either an electric or a gas kettle to be useful in the house. But the electric kettle has additional losses associated with generating and transporting the electricity.

I am not sure about how much energy is lost in the transmission of gas so that's an unknown factor. But presumably those losses are similar whether the gas is pumped to your home or a power station.

By extension, it's likely 'greener' for those of us with solar panels to use as little as possible of what we generate and export it all to power our neighbours' homes. There is, therefore, a genuine argument for net metering. However, while we're financially incentivised to do so, I'll continue to boil the electric kettle when the sun is shining.