Is it cheaper to heat up water via an immersion heater everytime you need it, or leave it on all the time?

[LadyOfWaffle]

Our only source of hot water is via the immersion heater, and because we use so much electricity we are trying to work out why. We used to leave the immersion heater on all the time, because it takes a really long time to heat, but DH has started turning it off (just had a cold shower ) but I think it's probably worse heating a tankful from scratch all the time rather than heating it once then keeping it warm - does anyone know?

Well, my bitter experience is that it's hellish expensive to leave an immersion heater on all the time.

We ended up with a £1400 electricity bill for a 1 bed flat that took us 2 years to pay off (although there was some evil British Gas dodgy stuff around that).

We were on a prepayment meter until very recently and could practically see the pennies counting down when the immerser was on.

Hows the cladding on your cylinder btw? We've just replaced ours and I do think it's making a difference to how long it stays hot.

God, I wish we had central heating.

SWITCH IT OFF FGS!!!

Its soooo expensive! Turn it on for 45minutes ish that should do it, then switch it off.

O, I just had a go at DH saying it was cheaper to keep it on - that explains £70 a week on the meter for electricity then! Thank god we are having central heating installed in the New Year.

We can't switch ours off

The switch doesn't work. Have been waitiong for landlord to fix fro 12 months. I suppose I shouldn't cpmplain, as prior to that we had no hotwater for 7 weeks.

It's the only way we can heat our water as the knbcakered old bnoiler deosn';t work.

£70 a WEEK!! My good god!

£15 max here.
We have 4bed detatched.

Wow IG that's really bad, bill your LandLord for the electricity used when it's on but you didn't want it to be on (that's what I would do)(not that it would work, but it would make me feel better!)

How well insulated is your tank? We lived in a flat with an immersion heater and found that we could turn it on once a day (or even once every two days) and still get hot water. How about getting a timer switch? We were going to, then we moved.

Will definitely be cheaper to heat as needed, not all the time - would you leave a pan on the stove constantly boiling, just so you could have a hot cup of tea when you wanted it? is the same thing...

(sorry slow to post was putting ds to bed...)

£70!! we have 5 beds, ours is £39/MONTH (no immersion heater though now thank god)

I know, we have 3 electric radiators heating what is basically a 3 bed house (ish) and it is so so expensive, hence the central heating being installed.

LL is shithouse.

He wouldn;t be bothered about the bilkl

When I had DS1, we had no heating (he was born in December 2004) and I didn;t want to bring a baby home to a cold house (it was an ice on the indise of the windows job) and his attitude was "oh well, just buy a blow heayter"!

Some men, honestly!
A blow heater, i ask you!

My dp is equally as clueless. Not so bad at things around the house though. But takes him a year to get around to changing a light buld or putting up curtain poles etc.

Leaving it on all the time is very wasteful and therefore expensive. You can use a timer switch so it is ready when you need it in the morning.

Imagine if your kettle was constantly on, of course it would cost more than boiling it when you need it.

I have been putting mine on, timed, 2 hours in morning, and 2 in evening.

Its a modern cylinder, and we only tend to have baths/showers in the morning. There's just me and dd, so I am thinking of only putting it on everymorning. OR is it cheaper for it too just slighty re heat the water that was heated up the evening b4.????

I asked a plumber the op's question once. he shrugged his shoulders, and said 'thats the eternal question.'

yeah cheers for that mate

1 hour at a time is enough to heat the whole tank and 1 tank is enough for you and dd I would think.

Cheaper to heat from scratch unless you have economy 7 as otherwise you are paying for the heat that escapes from the tank before it is used.

Definately cheaper to heat each time from thermodynamic principles. The heat loss is more when the temperature difference between the water and the outside is highest, so you are losing most heat to the environment when the water is hot - these are the only losses. If your tank is well lagged then there is less heat loss, but it's impossible to achieve perfect lagging (with zero heat loss) so it will always work out better to heat each use.