So my girlfriend just got billed 1350 POUNDS!!

Squidgy55

My girlfriend has just recieved an electricity bill for 1350 quid. She gets billed every 6months and payed 535 pounds in january. They claim she has been using 51 units a day and the average is 20. She has had an immersion heater on 24/7 but surely they don't cost that much to run. What's the average cost of running these things all the time?

Squidgy55

She lives in a 1 room/studio flat

PasturesNew

Squidgy55 wrote: »

She has had an immersion heater on 24/7 but surely they don't cost that much to run. What's the average cost of running these things all the time?

They are quite hefty. Most people would normally only turn them on when needed, for the minimum. A tank is huge so it's like boiling a kettle, then popping through every half an hour and flicking the switch again to keep it at the same temperature.

For example "If your immersion has a thermostat, it will switch off when water in the hot water tank reaches the temperature. ... If you house has a small 120 litre hot water cylinder, and the water starts off cold (4oC) and you heat it to a nice 55oC with your immersion, you will use 7 kWh to heat the water. With the daytime rate this will cost you £1.05"

Source: http://heatsave.actimedia.com/immersion.html

And she has it turned on all the time, so every time the temperature drops, it flicks itself on again to keep the temperature up. This could be a major part of it.

I don't know enough about these systems to actually do any rough calculations about how much it might cost to run one 24/7, but I live in a studio and I have never used mine. I have an electric shower, so just boil a kettle 2-3x to do the washing up.

jweb2k

That seems extorionate - immersion heaters cost around 30p an hour when heating, but hopefully with a working thermostat they wouldn't be constantly heating!!

Working it out - .30 * 24 * 182.5 (6 months) if it was on constantly and continued to constantly heat due to the thermostat breaking you'd be paying £1314... but that would leave the flat incredibly hot.. surely?!

Squidgy55

The Immersion Heater only heats water. She has electric radiators also but she hasn't really used them since march. We are aware that she shouldn't have left it on so much but 1885 pounds for a year? Is that reasonable?

KimYeovil

(The Immersion Heater may only heat water but the hot water radiates heat to the flat.)

No it is not reasonable to spend £1800. It is, however, very easy to do so and is entirely believable.

How warm is her flat? - you can not spend £1314 on electricity, as previously mentioned, without it being apparent.

Remember she spent £535 to January - that's before the cold snap. With electric heating during a very cold period to March that could easily account for two-thirds of the bill or more. The immersion heater is only a problem now, in summer, where the heating from the immersion heater does not supplement the radiators.

Your girlfriend has an electricity meter in her flat. Tell her to use it.

Magentasue

If you're saying that, over the year, your gf averages 20kwh a day using electric heating and keeping her immersion heater on constantly, it seems as if the bill is correct.

Electric heating is expensive to run. So are immersion heaters, electric showers and tumble dryers. Your gf should be using fewer than ten units a day now, maybe only three or four if she's out a lot. If she has an electric shower, she may not even need to put the immersion heater on every day, or 30-40 minutes a day may be adequate. If she has storage heaters rather than radiators, she is probably (or should be) on Economy 7 which means the immersion heater is using more expensive daytime electricity unnecessarily.

To save money, check whether Econ 7 is cost effective (probably is for storage heating but not for heating using energy during the day), consider switching to cheaper provider/tarrif and minimise use of anything producing heat.

PasturesNew

As a target, I think £40/month would be reasonable for her to try to achieve. She should start turning off everything she doesn't need, think all the time about what is running and check the meters daily.

glider3560

Are the opening/closing readings on the current and last bills actual or estimates?

Cardew

PasturesNew wrote: »

They are quite hefty. Most people would normally only turn them on when needed, for the minimum. A tank is huge so it's like boiling a kettle, then popping through every half an hour and flicking the switch again to keep it at the same temperature.

For example "If your immersion has a thermostat, it will switch off when water in the hot water tank reaches the temperature. ... If you house has a small 120 litre hot water cylinder, and the water starts off cold (4oC) and you heat it to a nice 55oC with your immersion, you will use 7 kWh to heat the water. With the daytime rate this will cost you £1.05"

Source: http://heatsave.actimedia.com/immersion.html

And she has it turned on all the time, so every time the temperature drops, it flicks itself on again to keep the temperature up. This could be a major part of it.

I don't know enough about these systems to actually do any rough calculations about how much it might cost to run one 24/7, but I live in a studio and I have never used mine. I have an electric shower, so just boil a kettle 2-3x to do the washing up.

An immersion heater left on 24/7 is not the reason for those sort of bills(unless it is in a very old uninsulated tank)

The average loss of a tank of hot water heated at 65C is between 2kWh and 3kWh in 24 hours. - you can often see the actual figure on a tank - a BSI standard - or look it up on line.

Whilst you shouldn't leave on a tank 24/7(unless you use huge quantities of water) the actual difference between timed heating and 24/7 heating is probably less than 2kWh as there will always be some hot water in tank even when timed and hence losses.

James123_2

You could always adjust the thermostat on the immersion heater - this is clearly marked under the cap which houses the unit on the top (usually) of the tank. Turn off electricity first, if you're unsure. If this is set too high then the tank will be constantly topping-up every time even the smallest amount of water is dispensed.
As others have said, an immersion uses 3kw which, in simple terms, is 3 units an hour with a typical warm-up time of 30 minutes from a modest temperature. So, assuming a typical 10p a unit rate, this equates to 15p per top-up. Personally, unless it' a big household, I'd always time the immersion so that you're in control of costs - 2 x 45 minutes AM/PM. An old, uninsulated tank (without foam) will lose heat rapidly. Your tank might even have two separate immersion heaters (middle and top) if you've been on Economy 7 at some point. But that's another story!!