Economic kettle

Shedman

Even if using an electric kettle was slightly cheaper (which is unlikely even if a electric kettle is 60% efficient vs 25% for a gas kettle according some reasearch I found) the cost of buying the new electric kettle would probably have a payback period in excess of 2 years.   The big advantage of electric kettles is that they switch themselves off and don't boil dry and melt as happened to the MiL....

QrizB

In the interests of SCIENCE! I have just weighed 500g of water into my kettle, plugged it into my energy monitor and boiled it. My kettle is a £15 Argos Cookworks cheapie.

• The kettle drew ~2200W
• It took 1 minute 38 seconds to boil
• It used 0.059kWh
• On my current tariff of 20.68p/kWh, it cost 1.22 pence.

I hope this contribution to the pool of human knowledge is appreciated as much as my pot of tea will shortly be

mellyflewus

t0rt0ise said:

ballisticbrian said:

The specific heat capacity of water is 4,200 joules per kilogram (litre) of water. No one can build a kettle that avoids this.

You could use gas boiler for warm water and pour that into the kettle?

In summer (and winter as well if you have a warm kitchen), if you have cold pipes, fill the kettle with a little water AFTER pouring each cup of tea so the water in the kettle comes up to room temperature before you start boiling.

Ooh yuck. Water that's been standing before boiling has an odd taste. Has to be freshly drawn water.

i also wouldn't consume water that's been through the heating system because i have worries about dirt, contamination and listeria etc.

i know that modern heating systems have dirt magnets applied and that listeria is rare but still.

matelodave

My mum had one of these - https://www.robertdyas.co.uk/breville-hot-cup-dispenser?gclid=CjwKCAjw-sqKBhBjEiwAVaQ9a0He_Wu96BGmuA5X-0c-X6WY3bk9w-KCdDFdLBtllPX3j3p7MsfSkBoC7p0QAvD_BwE. Probably about as economical as you can get as it only boils the exact amount of water that you need.

FreeBear

QrizB said:

In the interests of SCIENCE! I have just weighed 500g of water into my kettle, plugged it into my energy monitor and boiled it. My kettle is a £15 Argos Cookworks cheapie.

• The kettle drew ~2200W
• It took 1 minute 38 seconds to boil
• It used 0.059kWh
• On my current tariff of 20.68p/kWh, it cost 1.22 pence.

I hope this contribution to the pool of human knowledge is appreciated as much as my pot of tea will shortly be

The maths tells us that it would need 0.046KWh to boil 500ml of water, so allowing for inefficiencies of the kettle (say 90%) and measurement errors (10%), your 0.059KWh is pretty close to the mark.

Using a kettle over a gas hob would have used a lot more energy as a substantial amount of heat disappears around the side of the kettle. Perhaps as much as 75% of the energy is wasted.

ballisticbrian

FreeBear said:

The maths tells us that it would need 0.046KWh to boil 500ml of water,

Does depend though on the starting temperature of the water which can vary wildly.

Verdigris

Using a kettle over a gas hob would have used a lot more energy as a substantial amount of heat disappears around the side of the kettle. Perhaps as much as 75% of the energy is wasted.

The wastage depends a lot on how high a flame you use. If you hold your hand above the kettle you can feel the spilled energy. Turn the flame down until you can barely feel any heat. This applies to saucepans as well, of course, so use a burner of the appropriate size for the diameter of the pan.

chewyluis

It's cheaper to buy a coffee from McDonalds than boiling your own water. Consider this option, it's something I do several times a day but i have a McDonalds on my doorstep.

Ultrasonic

chewyluis said:

It's cheaper to buy a coffee from McDonalds than boiling your own water. Consider this option, it's something I do several times a day but i have a McDonalds on my doorstep.

Not sure if you were being serious? It's certainly not true  .

Verdigris

Indeed. I justify my bean-to-cup machine on the basis that it pays for itself, capital and running costs, in a year or so of savings over coffee shop prices. And there are no disposable cups to !!!! up the environment.