is it more economical to have our tea urn on constantly, or to turn it off/on each time we use it?

Question

Hi there.

We have a tea urn named Ernie, (original eh). Anyhow, he serves us well, and delivers us our constant supply of caffeine rich beverages. Without him, well i really dont know where we would be,

So, sometimes Ernie gets turned off, to save electric. Obviously, during this time, Ernies water cools. Then when we turn him back on, it takes about 10 - 15 minutes to get him back to full brewing power.

So my question is, is should we leave Ernie on, so he only kicks in when the temperature drops a little, also meaning that we can have spontaneous cups of tea, without the need to pre empt a caffeine kick by 10-15 mins, or, is turning him off and on the best solution. We have a cup every 60 - 90 minutes.

We are also considering getting Ernie a jacket, and a little bobble hat, this would also help his efficiency

Ernies usually holds about 5 litres of water, and we fill him up every day,.

Answer 1

sounds to me like Ernie might be overkill - if I understand you - you are boiling less than five litres over the course of the day.
Perhaps an instant electric kettle would be more economical.

Answer 2

You could work it out for yourself using the specific heat capacity of water and the thermal energy transfer, however at a rough guess it probably makes little difference unless you leave it for much longer. But for 5 litres a day you would be much better off getting a kettle. A hat and coat would save you quite a bit of energy as the heat dissipation will be greatly reduced and therefore the required energy to keep it at a constant temperature will subsequently be reduce and besides he could look so cute..........................

Answer 3

If its not constantly at a boil, just reheating once the water temperature drops below a certain level, it's cheaper to leave it on once boiled.

But do get an insulating jacket, this will increase the time between reheats.

Answer 4

not only wasteful in energy
it spoils the taste of the tea by removing oxygen
get a kettle

Answer 5

Dress him up and leave him on - he should have a thermostat which will take care of the economy.