ECO kettle - I don't get it

Stuart Wright

Eco Kettle - Introduction to the Eco Kettle

What's the difference between filling a normal kettle up with the correct amount of water and pressing the ECO kettle knob to fill its boiling chamber up with the correct amount of water?   It's the same thing.  People can't be bothered to look at the amount - usually because it's measured in centilitres and nobody knows how many centilitres are in a mug full.
Is the ECO kettle simply all about making people look at the amount they are boiling?

IronGiant

Mostly, it also has a 2.2kW element so that probably makes it slightly more efficient when boiling small quantities of water.  Other than that you might just as well buy any kettle with a 1 cup marker on it.  You can get kettles with a temperature setting like this one Philips HD4632/20 Eco Temperature Control Kettle, 3000 Watt, 1.6 Litre: Amazon.co.uk: Kitchen & Home which would give a small genuine saving. Note this kettle also claims to save 66% in energy by only boiling the water you need

DOBLY

Smells to me of marketing hype.  There might be a small saving as the chamber that the water is heating up in is smaller than a regular kettle, so it comes to the boil sooner, but this will have a pretty small effect on the efficiency.

I know that on our kettle, 2 mugs worth of water for tea comes to the "750" ml? mark, so that is how much I put in the kettle most often.

I don't remember the last time I filled the kettle, only to pour some of the water away, unused.

I suppose that their marketing has worked to some extent - I visited their website, watched the little video etc. but won't be buying one of their products...

And as the old saying goes : always use freshly-drawn water - when making tea, as it tastes so much better than water that has been boiled time and time again.

EarthRod

An electric kettle is not very efficient and an ECO electric kettle is a contradiction in terms.

A better way is to put your cup of water in a microwave. Quicker to boil and much less power used.

Care needed though!

johntheexpat

The heat capacity of water is about 4.2 J per ml per C. (IIRC)

So to boil 500 ml of water from 10C to 100C uses 500 X 4.2 X 90 J which is a touch below 190KJ ( so a 2KW kettle would take about 85 seconds to boil it).
You need maybe 300 ml for your cup, so the excess is 40% of that ie 75KJ

75 KJ is 0.0208 of a KWh

A Kwh is about 10p, so each excess cup wastes 0.208p.  The cheapest kettle is £35.

So, after 3500/0.208 cups of tea, you have paid for the kettle.

Are you prepared to drink 17,000 cups of tea to save the planet?

DPinBucks

Not necessarily.

An electric kettle is 100% efficient; all the power is converted into heat.  A microwave oven is about 60% efficient.

So the latter gains when you're not wasting heat, such as the water left at the bottom of the kettle.  Also, a microwave is not recommended for boiling water in a cup or mug; it can be very dangerous.

EarthRod

We use a microwave to heat a couple of large mugs of water - 700 watts, clean water, no water wastage and only takes a few minutes. Not dangerous at all - timer switches power off. Clean, efficient, quick and easy.

However, I didn't take into account the energy losses in a microwave:
1. Heat generated from the magnetron.
2. AC power transformer losses.
3. The light in the microwave.
4. Turntable motor drive.
5. Control circuit.
6. Microwave fan.

The above account for about 35% energy loss in total, so the microwave requires about 1.1KW to deliver about 700W.

A kettle is not 100% efficient - nowhere near. But it is certainly more efficient than a microwave taking the above losses into account.

danmc_82

Affraid not, nothing on earth is 100% efficient.

stanstedpete

An electric space heater is virtually 100% efficient.

danmc_82

Maybe 99% but like I said nothing is 100%. If you created something that was you'd be a billionaire.