Economic kettle

FreeBear

ballisticbrian said:

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.

Good point. The 0.046KWh is based on a starting temperature of 20°C at sea level and heating the water to ~100°C.

QrizB

... and in practice, of course, a cheap automatic kettle (like mine) needs a flow of steam to trigger the switch so it will always heat for longer than is required. If you can judge exactly when to turn it off manually, or have a kettle with a thermocouple that knows the temperature of the water, it will shut off earlier and save a fraction of a penny.

bob_a_builder

"The main economy is only boil what you need & not a kettle full just for one cup"  

Oo - if only I could convince "Mrs Builder" of the logic of that !

and the fact that just because a radiator isn't hot at this particular time doesn't mean the heating is off !

Verdigris

If you subscribe to the theory that water at 96 degrees makes the best tea/coffee then a kettle that switches off at that temperature will save a little bit of energy. However, it would be many years before you get the extra capital cost back, from the extravagant prices that I've seen.

The best tea come from water boiled on a Aga. I think this is because the heat is evenly distributed and knocks less oxygen out of the water. Sadly Agas aren't energy efficient. I think gas may be better than an electric kettle in this respect, too.

shinytop

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

My Nespresso machine makes my chosen tipple of a lungo+espresso in 90 seconds.  It's rated at 1260 watts so about 0.032 kWh.  Drinking coffee must be much greener than tea.     

Gerry1

You're unlikely to find a faster or cheaper electric kettle than this one at Argos at £9.99... ... unless you order it on ebay at £8.99 !

FreeBear

shinytop said:

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

My Nespresso machine makes my chosen tipple of a lungo+espresso in 90 seconds.  It's rated at 1260 watts so about 0.032 kWh.  Drinking coffee must be much greener than tea.     

Once you have factored in the cost of roasting the beans, grinding them, and then sticking in to little (non-recyclable) pots, tea is much greener. Even better if you go for Japanese Green Tea (but not that stuff in non-compostable bags).

But hey, I likes my espresso coffee freshly brewed on an induction hob

hubb

I have always wondered why someone hasn’t invented a kettle that has a thermos flask reserve, keeping the water hotter for the next boil. In fact, we flask any extra water we boil ready for the next time.

Verdigris

Why not just put in the amount you want in the first place? Saves the risk of scalding injuries.

Gerry1

hubb said:

I have always wondered why someone hasn’t invented a kettle that has a thermos flask reserve, keeping the water hotter for the next boil.

They have.  Quooker

But not exactly money saving...