immersion heater

destiny_star2006

Hi guys im getting an immersion heater fitted tomorow as i have a coal fire and im sick of having to put the fire on to get hot water for baths etc so im hoping this will be a good thing..but
could someone tell me how to run this efficiently as my mil says to just leave it on all the time as it wont cost half as much to keep hot as if it would if i would let it go cold and then reheat again,,what do you guys think and how do you use yours...people have told me it will cost a fortune in electric but ive got a meter in so ill be able to keep tabs on it...thanks for your help and advice again guys in advance:beer:

tanith

If you have no alternative ie: gas central heating boiler, and you have to light a coal fire all through the summer for heating water then just for convenience sake its got to be better , but its going to cost you to hear your water by electric...
I am sure people will all have thier own power saving suggestions... and will be along shortly.. I can't really see how having it on constantly can be the most efficient way...

Cazza

I have an immersion and have just received my electricity bill for the 2nd quarter. According to the bill, we used 12 units per day last year, this year we're using 4 units per day.

The only difference I can think of is that this time last year we have the immersion on 24/7. Now, our immersion goes on once per day, for about 1 - 1.5 hrs (we have no timer, so do get one fitted as it means you don't forget to turn it off!)

Rikki

A friend of mine just puts his immersion heater on once a day for one hour. I'm not sure what the bills are but this is all thats needed for two showers and water for washing up.

Cardew

destiny_star2006 wrote: »

as my mil says to just leave it on all the time as it wont cost half as much to keep hot as if it would if i would let it go cold and then reheat again,,:beer:

Then using exactly the same principle it will be cheaper to keep your kettle boiling all day as if you "let it get cold and then reheat again" - you get the picture.

The cheapest way is to have it on for as short a time as possible and still have enough HW for your needs.

You will have to experiment to get the correct timing.

That said, leaving it on constantly will not cost a huge amount more than having it on a timer - but enough to be worthwhile.

Oblivion

Cardew wrote: »

Then using exactly the same principle it will be cheaper to keep your kettle boiling all day as if you "let it get cold and then reheat again" - you get the picture.

A slightly bemusing analogy since immersion heaters have thermostats fitted which can be adjusted to control the maximum temperature of the water as well as switch the supply on and off as needed.

We use the Economy 7 electricity tariff here which means our electricity is cheaper at night. Our immersion tank is on an electric timer, which can be overridden if we quickly need more hot water during the day, so that most of our water heating is done during the cheap night time rate. Since both of us prefer to shower rather than bath, a tank full of water generally lasts us most of the day.

Dave.

destiny_star2006

thanks for all your answers apreciate it

Andy_Hamilton

Leaving the heater on all day will loose heat which your paying for.
You need to find out how much water you actually need. Try starting with one hour and reduce/increase as you need it.

Turn the heater on for around 1 hour before you need it possibly twice per day (fit it with a timer if you can). Then, if your going to use the water and don't need much more make sure it's off before you use a single drop. There is no need to heating up again when your going out for the day.
As a very rough guide a 3KW immersion heater will use 3KWH (3 units) per hour. So 2 hours per day would be around 6KWHs (units) per day would work out as 90p per day.

This is more important:
If you open the aering cupboard and it's warm, your paying to warm that cupboard. If any boiler is un-lagged it can loose upto 8KWH just heating that cupboard. Insulating it can reduce it to under 1.5KW.
A well lagged boiler will save you anything upto £240 if the boiler is left hot all the time.
A boiler "jacket" is less than £12 in B&Q and Tesco superstores. They pay for themselves in a mater of months. My boiler can keep water HOT for 3 days

Cardew

Oblivion wrote: »

A slightly bemusing analogy since immersion heaters have thermostats fitted which can be adjusted to control the maximum temperature of the water as well as switch the supply on and off as needed.


Dave.

Why is it a bemusing analogy?

It serves to illustrate the(thermodynamic) principle that it uses more energy to maintain any body at a constant temperature, than let it cool down and then reheat it to the same temperature.

Another analogy.

If your contention is that it is cheaper to leave your 'thermostatically controlled immersion heater' on 24/7 as it costs more to let it cool down and reheat; then if you go away on holiday for 3 weeks you should leave your immersion heater on 24/7. Exactly the same principle.

P.S.

You state the thermostat controls the temperature of the water as well as switching the power on and off


How do you think a thermostat controls the temperature of the water other than by switching the power supply "on and off as needed"