Efficient way to boil water

A_Nice_Englishman

The smallest possible electric kettle should be the most efficient. The amount of water to just cover the element will less than a larger kettle so it will be easier to only boil as much as you need and there is less material in the kettle itself to heat up.

Having said that we are talking differences of much less than a penny per use so a well made kettle that lasts many years may be better than a cheap n cheerful one even if the latter uses less electricity.

neilmcl

There's plenty of studies into this, just google it. The general consensus in terms of energy efficiency, running from lowest eff/highest cost is microwave, hob (gas and electric work out similar due the amount of energy wasted with gas), electric kettle, and finally induction.

r2015

I do wonder if a lower power kettle running for longer might be more efficient -

No, because you get fed up waiting for it to boil so you wander away and when you come back you have to switch it on again.

I used to have a 2kWh kettle but it took a lot longer to boil, obviously, than my new 3kWh kettle and I find it uses less electricity overall.

welshbookworm

An acquaintance of mine boils a full kettle, makes a tea and then puts the rest in a flask to make tea throughout the day
Says that's the cheapest way.

Raxiel

We bought one of these http://amzn.eu/aPI40b0

Like all electrical elements, it's close to 100% efficient at turning electricity into heat, but the kettle's construction means a lot more of the heat remains in the water.

Less escapes during boiling
Water stays hot for longer, so less energy wasted re-boiling water, all stainless steel so the water tastes fine even after being sat in there a couple of days.
'only' 1.2 litre so even full its not heating masses of water, which is just as well because it's element is a lot less than 3kw, but it still only takes seconds to 'top up' heat water that was boiled within the last hour.

Of course it'll take a long time to pay for itself in terms of energy savings, but it's a nice, well made item so we're happy with it.

neilmcl

Raxiel wrote: »

We bought one of these http://amzn.eu/aPI40b0

Like all electrical elements, it's close to 100% efficient at turning electricity into heat, but the kettle's construction means a lot more of the heat remains in the water.

Less escapes during boiling
Water stays hot for longer, so less energy wasted re-boiling water, all stainless steel so the water tastes fine even after being sat in there a couple of days.
'only' 1.2 litre so even full its not heating masses of water, which is just as well because it's element is a lot less than 3kw, but it still only takes seconds to 'top up' heat water that was boiled within the last hour.

Of course it'll take a long time to pay for itself in terms of energy savings, but it's a nice, well made item so we're happy with it.

You mean like 80% close

lammy82

neilmcl wrote: »

You mean like 80% close

Where does the other 20% go if not heat?

neilmcl

lammy82 wrote: »

Where does the other 20% go if not heat?

Fair enough, I slightly misread the post. The element itself will be pretty much 100% efficient at converting energy to heat but that's the same with pretty much all kettles. Heat dissipation and transfer to the kettle body itself will reduce the overall energy efficiency down to around 80-90%.

Heedtheadvice

The original question was about efficiency. OP you have our answers already posted but I do wonder if you really mean lowest cost or energy consumption. Some posters probably correctly have answered that too.


........I suggest only boil water on sunny days using a solar heater (great big lens or parabolic reflector) - not necessarily very efficient but very cheap! - and reduce consumption (drink more cold beer! :rotfl:


Seriously though you will find it difficult to beat an electric kettle. If you need hot water but not necessarily boiling (such as for coffee) then those with selectable temperature are quite handy.

Naf

neilmcl wrote: »

A totally inefficient way to heat up anything.

Depends if you're talking about energy efficiency or cost efficiency. Since there is a large disparity between the cost of electricity and gas it is quite possible for the less energy efficient gas hob to be more cost efficient than the electric kettle.