News1 min ago
Immersion Heater
10 Answers
We take advantage of overnight cheap electricity to use washer, dryer etc. Can any one tell me how many hours it takes for the immersion heater to come to full heat as I am getting paranoid about using un neccessary power! Our tank is about 3' 6" high and at the moment we have it on from 0130 to 0630 and that gives us water for the whole day. Could I reduce this by one or even two hours without reducing the availability of hot water??
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I guess having it come on at 3:30 wouldn't hurt. You'd still have a tank of hot water. You'd probably find that the saving would hardly be noticeable though because the element has a thermostat that switches it off when it's up to temperature.
Because of the thermostat, the element is only on intermittently anyway ..........
Because of the thermostat, the element is only on intermittently anyway ..........
Bit of a guess here but that sounds like about 166 litres. 166 Kg
now we get to more guesses
Say you want to go from 5 degrees to 35 degrees that's a 30 degree change
The energy to do that is 4200x166x30 = 20 MJ (4200 is the specific heat capacity of water)
If your immersion heater is 3Kw that's 3,000 Joules per second
dividing one by the other gives you 6700 seconds or about 11 hours.
That's heating the entire tank from cold - if your tank is only heating up 15 degrees it's half that. If your immesion heater is 6Kw it's half that.
You see about the guess work.
Also if you have central heating switched on it depending in the system it may be taking its heat from the hot water tank which cools the water.
Not enough information I'm afraid but perhaps you can see how you can do the rough estimates
now we get to more guesses
Say you want to go from 5 degrees to 35 degrees that's a 30 degree change
The energy to do that is 4200x166x30 = 20 MJ (4200 is the specific heat capacity of water)
If your immersion heater is 3Kw that's 3,000 Joules per second
dividing one by the other gives you 6700 seconds or about 11 hours.
That's heating the entire tank from cold - if your tank is only heating up 15 degrees it's half that. If your immesion heater is 6Kw it's half that.
You see about the guess work.
Also if you have central heating switched on it depending in the system it may be taking its heat from the hot water tank which cools the water.
Not enough information I'm afraid but perhaps you can see how you can do the rough estimates
Thanks for all your input guys. If I understand you (all) correctly, the actual heating up of tank to full heat only takes an hour approx? After which the thermostat keeps topping it up?? If this is the case, I can surely then just put it on for an hour/two hours say in the cheap period, then let the thermostat keep it at heat??? Sorry to be obtuse!
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