# electrical usage



## Pudsey_Bear (Sep 25, 2008)

We've just been going over our electricity bills and are looking at ways to save a little money.

My first thought was how much does my laptop use, the label on the charger says 1.7 amps @ 240v.

What the charger label says is :-
input 240V 50htz 1.7A (1.7A) = 408Watts
output 20V 3.25A (3.25A) = 65Watts


now I don't run a battery on it, so when it's on, it's only powering the laptop, when I shut the lid, it goes into standby, and I just have to put my password in to wake it up.

Is this the best way to run it, should I shut it down, or better still shut it down and turn it off at the socket?

I worked out the watts consumed to be 408 watts, it that per hour or what, surely it's not like running an electric fire, I assume that it's using 408amps per hour as it has to put in the 240V/1.7A to give me the 20V/1.25A.

If this is true, then I won't be using it too much.

HELP

Kev.


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## pippin (Nov 15, 2007)

Feel it!

You will be surprised how hot it gets - that's where your Watts are going.


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## sallytrafic (Jan 17, 2006)

I doubt very much that you are taking 408W from the supply.

Its not as straightforward taking the figure for current and multiplying by the voltage to get the Watts.

For a start those currents and voltages will be limits not actual values.


If the power supply was drawing 408W and only giving out 65W then the missing 343W would be make it more than a little warm it would be able to give background heat to your MH


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## Pudsey_Bear (Sep 25, 2008)

I know the heat given of by an electrical device is an indication of how inefficient it is to some extent IE incandescent light bulbs are, I believe about 90% inefficient or thereabouts so electric fires should be 100 efficient as it's all heat, but I think even they fall down on the conversion of energy to heat, (60's science lesson) anyway, before I go off the point too much, my charger isn't getting that hot, I had some that almost glowed in the dark.

So boffins and boffinesses, how much do your laptop chargers use, and what is the cheapest way to run them, I think I wiil be turning mine off at the socket from now on, someone has to save the planet for the little ones.

Kev


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## CliveMott (Mar 10, 2008)

Tha Laptop power supply is designed to work over a wide voltage range, typically 90 - 240 volts ac to suit both European and American markets. The amps figure stated is that taken when the laptop is running all its drives, the processor at near 100% and the graphics system running balls out on some idiotic game and the mains supply is at the lowest figure stated around 90 volts. 

Hope that helps

C.


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## DTPCHEMICALS (Jul 24, 2006)

You should be knighted for your example Kev. Trouble is the uk produces about 2% of carbon emissions. If we stopped everything it would not make a blind bit of difference. The emerging maufacturing nations would take up our savings. Shipping must be one of the heaviest poluters now.

And mh`s out and about in summer. Sellfish swines :lol: :lol: :lol: 

dave p


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## GEMMY (Jun 19, 2006)

Dave, you've just doubled the UK CO2 output.Latest figures indicate that UK output is 1% .By the way,figures released a couple of days ago indicate that China has overtaken America as chief dirt bag of the world 8O 

tony


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## Pudsey_Bear (Sep 25, 2008)

Just found this little tit bit, not sure of the accuracy of it.

At Homecamp, a figure was thrown out that if something consumes 1W continuously, it will cost a pound a year to run.

1 watt * 1 hour = 1 watthour
1 watthour * 24 Hours = 24 watthours
24 watthours * 365 Days = 8760 watthours = 8.76 kilowatthours
1 kilowatthour = 8.304p (http://www.tescoenergy.com/tesco/UtilityResources/expert.html )
8.76kwh * 8.304p = 72.74p

i.e. Running 1 watt for 1 year = cost of 72.74p.


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## JeanLuc (Jan 13, 2007)

Console yourself with the knowledge that your computing power usage is minimal compared with today's data centres on which we all rely.
It is estimated that Google's facility next to the Columbia River in Oregon will require over 100 megawatts when it is fully on-stream in 2011. It has been built near a hydro-electric dam and uses water from the river for cooling. I believe they will have solar panels too - rather more than a typical motorhome!

Oh, and that's just one of around 36 data centres that Google has around the world.

Philip


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## Pudsey_Bear (Sep 25, 2008)

DTPCHEMICALS said:


> You should be knighted for your example Kev. Trouble is the uk produces about 2% of carbon emissions. If we stopped everything it would not make a blind bit of difference. The emerging maufacturing nations would take up our savings. Shipping must be one of the heaviest poluters now.
> 
> And mh`s out and about in summer. Sellfish swines :lol: :lol: :lol:
> 
> dave p


I'm glad that you're only joking Dave P, some might agree with you otherwise, and we all know if nothing is done to at least try and turn this climate around, it's our descendents who'll be carrying the can.

There are those of course who believe and even preach that global warming is a natural thing and not to worry, they may even be correct (but I doubt it) even so it won't do the planet or our wallets any harm to cut back on any energy use any way we can, how much more encouragement do we need to save money, most energy use is out of lazyness, it's too far to the off switch, if we didn't have so many remotes, the planet could lose a few power stations.

Seemples, Turn the bugger off.

Kev.


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## sallytrafic (Jan 17, 2006)

This is what you need Kev or something similar for all portable appliances, but only buy one per street or extended family and lend it. Otherwise you might be making things worse rather than better.

>maplins about £15<


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## Pudsey_Bear (Sep 25, 2008)

Thanks Frank, I have an Aldi/Lidl one already but it gives very odd readings.

Does anyone have a spread sheet already set up for working out gas and electricity bill, if so I'd welcome a copy.

OK we live in a decent size house, built in 01 so fairly energy efficient, double glazed, very well insulated timber frame, so we're not heating West Yorkshire, but we're getting huge bills, there coming to check the meter at the end of the month it's that bad, so it might be the meters fault in the end.

The immersion heater (11") seems to be the main user of electricity, the energy meter for the whole house says we are using around 30-40p per hour, it's a Titan 110 litre big white thing, very well insulated, and hot water is pumped around the house.

I'll give you a rough idea of what we have in the house

3 x LCD TV's @ 150 watts <3watts standby, but they're usually off when not in use.
1 x CRT TV @ 150 watts again gets turned off

4 x laptops + 1 x Desktop, 2 x laptops are used 2-3 hours per day, desktop is on about 8 I think other laptop not used too much.

3 x Sky boxes 2 are + and need to be on to record, but Sky says they don't use much, but don't say how much, other is std and turned off when not in use.

1 x PVR used about 1 hour per day (bedroom) but on standby 24/7

1 x dishwasher per day

1 x washing machine load per day on average

Induction hob maybe 30 ins a day on average

oven 30 mins a day

Lights, most single lights are low energy 7 watts things.

Kitchen has 12 x 12V 50w halogens

hallway/staircase/landing has 10 x 12V 50w halogens

2 bathrooms have 8 x 12V 50w halogens each

so 38 of those @ 50w = 1,900w @ 12v = how much @10p per Kwh ?

I have no idea how to work out the halogens total wattage, IE I know 12 x 50 = 600 watts, but that's @12v, what is it in real terms? I know they're supposed to be cheaper to run, but I can't find a proper figure.

I drive everyone up the wall by going around turning stuff off, (even the microwave, those LED's must cost something to run, I'm even pi$$ing myself off trying to save a penny here and there, our lass woks very hard to pay the bills (still no job) and it does my head in, the kids are aware that it cost money, but they aren't seeing the bills, we currently pay £137 per month DD just for Electric, and we are not in front, far from it.

So if anyone can shed some light on what we are doing wrong, please, do tell.



Does anyone have any recent figures on which is better, to leave the immersion on or to have it timed, and yes I know pumping the hat water round does have a cost, but can it be so much.

Any energy saving ideas I might not have thought of short of the big off switch.

Kev


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## EJB (Aug 25, 2007)

I used to be an anorak....it was too much effort.
Now....if it's not actually in use it's not plugged in.
I have never seen the logic of using 'standby' modes......standby for what? Just in case there is an emergency and those few seconds count :wink:


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## Pudsey_Bear (Sep 25, 2008)

If you have a recording device, and it's set-up to record, it MUST be on standby, also anything that has to do something at a certain time such as an oven etc.

However I think anything else left standby is mostly lazyness, except in the case of turning the TV off to answer the phone etc.

Kev.


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## SpeedyDux (Jul 13, 2007)

Kev,

I suspect your household definitely must be big electricity users when you aren't running round switching things off. :wink: 

I live in a modern 4 bedroom house and my electricity supplier has just written to me to say they are reducing my monthly direct debit to £12 because they owe me too much! :lol: 

SD


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## Pudsey_Bear (Sep 25, 2008)

Who are you with SD, We're thinking of switching as soon as the meter has been checked.

Kev.


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## SpeedyDux (Jul 13, 2007)

Kev,

It's EDF for both electricity and gas. I switched to them in early 2008 and got a deal that fixed both tariffs until the end of 2010. I don't know what current switching deals are on offer that would suit your somewhat heavier level of energy usage, but you could try the Youswitch and Moneysaving Expert websites for advice.

Meanwhile, I suggest your family tries living in the dark and telling stories to entertain each other. And maybe doing less washing .. :wink: 


SD


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## Pudsey_Bear (Sep 25, 2008)

I appreciate any advice, that allows for a normal life, but going back to the dark ages isn't going to work.

Kev.


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## Fatalhud (Mar 3, 2006)

High Kev
You have to get your head around the fact that a Watt is a Watt
the only difference is the voltage it is supplied at

so if you have 1900 watts at 12volt it will be 1900 watts at 230 volt
the only difference is the current used give or take a bit for the efficiency of the transformers
158 amp @12volt
8 amp at 230 volt

To replace all 38 50 watt lamps at once would cost a bomb
but what i do is every time one blows I replace it with a 30 watt lamp

Her in doors likes it nice and bright, but she hasn,t sussed me yet

You say your hot water is constantly pumped

I am not a plumber but I think this is just to give you hot water at the tap as soon as you turn it on
In doing this heat will be lost as it is pumped around the house causing the Immersion to work harder
Can you not turn off the pump 
plus fit a time clock so you can heat the water around the times you use it most

Alan H


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## Pudsey_Bear (Sep 25, 2008)

Thanks Alan,



> so if you have 1900 watts at 12volt it will be 1900 watts at 230 volt
> the only difference is the current used give or take a bit for the efficiency of the transformers
> 158 amp @12volt
> 8 amp at 230 volt


 I'm not sure that's the case, what you say makes perfect sense, but what would be the point in everyone switching to these lights if they use the same amount, not saying you're wrong, just that I don't understand it.

Kev.


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## Rosbotham (May 4, 2008)

No, Alan is correct. A 50W halogen bulb that's running at 12V will pull 50/12 = 4amps at the bulb. A 50W halogen bulb that's running on a 240V supply (obviously a different bulb to the other one!!) will pull 50/240=0.2amps supply....either way it's burning 50W.

The 12V ones you have are probably (marginally) worst of all worlds because the transformer in the unit to step down mains supply to 12V won't be 100% efficienct so will burn a bit of extra power as well.

Either way, although you're a high-usage household (like us...we have 3 laptops & a desktop on most of time as I'm a homeworker so get through c20-25KWH/day), your lighting isn't helping you. If you've got all of the lights on, 38 x 50W = 1900W = 1.9KWH/h = 19p per hour. Doesn't sound much, but multiply it up...

There are LED replacements you can buy which only use 1W, but they come in at best part of a fiver each (versus I pay a fiver for 20 in Costco for the standard ones!) so it's best to wait until the others blow and even then the economics are dubious IMHO. It's a moot point at this time of year, but inherently power doesn't just disappear...if a conventional bulb uses more power than a low energy one, it's dissipated in the form of heat. Now, at this time of year it's unwanted heat, but in winter, all that you're doing is heating your room with the bulbs, which means the theromstat on central heating will trigger it off more quickly, so by moving to low energy bulbs you're just shunting power usage from your lights to your central heating. Gas is cheaper than electricity KWH for KWH, but if you've got electrical heating, you're just shunting the issue around.

I'm guessing from your post that you don't have gas heating and heating's all done from the immersion heater? If so that's a pretty inefficient system but you're stuck with it I suppose. Have you tried turning the thermostat down on that? Might also be worth considering fitting a timer to the circuit so it only heats a couple of times a day - having said that if your tank's only 8 years old, it'll be pretty energy efficient. Also NB if you do fit a timer, an immersion heater pulls large amounts of power (typically 3KW) so don't just get a cheapie one...ask advice & get an electrician in.

I wouldn't get too worked up about any reasonably modern consumer equipment (TV, Sky, phone chargers etc) being left on standby...contrary to the green lobby propaganda, most such kit draws <1W when on standby so even if you had 50 appliances it'd only be the same as leaving a single light bulb on...or approx 10p/day.

NB you sound like you may have Sky multiroom - if you have any premium channels you must leave your boxes on 24/7 and connected to a phone line, or you'll get a snotty letter threatening to charge you full subscription for each individual box.

EDIT : forgot to mention. If you're really desperate to track down what's using power - and at your usage levels it's probably worth the investment - it's probably worth looking at a Efergy energy monitor. They cost £40 but are far better than the cheapie plug in ones...what happens is you plug a gizmo around the input mains supply to your house, and it can tell you the instantaneous power usage right across the property on a remote display that you can carry around. So you can e.g. turn on the lights in the kitchen and see quite how much your power usage surges.


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## Pudsey_Bear (Sep 25, 2008)

Thanks Rosbotham,

That's a lot to take on board in one mouthful, We do have gas central heating, even got underfloor heating upstairs and down, or we would have if it wasn't for W4nker sparky's and plumbers ripping us off, and it still not working, the house was wired by a sparky with one eye, and it's still not finished (ex hubbys mates etc) hence the need for the immersion heater, I could go on, but won't.

We have an Effergy monitor too, I just set it to 12p per Kwh, and to beep at 3kw, had to change it to 4Kw as it goes off as soon as you use anything in the kitchen, if the kettle happens to be on.

Kev


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## Rosbotham (May 4, 2008)

Ah, so you do have gas. Imersion heater should be turned off in that case as using the gas supply is more efficient (it's unusual to have one where there's gas central heating in a new build...only reason we have one is because I kicked a fuss up because there was a fitting for one). I'm guessing you probably have a similar system to ours, then, given it's of the same vintage...hot water is fed at mains pressure, going through the tank en-route - in essence tank is more of a heat exchanger than anything else.

I'm not surprised that your Efergy alarmed when you turned the kettle on...they do draw a bit of juice. Mrs R just had the iron on at same time as the oven downstairs, and that sent our usage surging to 4.5KW. It's very easy to get anal about these things...

If it helps, during the day with TVs off but desktop + laptop powered up, together with router and wifi, plus 3 heated aquarium tanks, my box is generally reading c0.5KW. If you're reading much above that, it's time to start wandering around looking for power-hungry things to turn off.


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## Pudsey_Bear (Sep 25, 2008)

it's at 4.4 kw, as I type, no cooking, 2 TV's on I'm just going up to turn off the Immersion, that'll bring it down to about 1kw I think.

Kev.


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## Pudsey_Bear (Sep 25, 2008)

for some reason it's fluctuating between 1.2 and 1.8 Kw, I have on sky and my lappy, lad upstairs is on his X box, immersion is OFF, we have a small chest freezer, and an A rated American style but not size F/Freezer.

it's doing me loaf in big style.

kev.


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## Rosbotham (May 4, 2008)

Yes, seems an awful lot. Regretable thing is if the Efergy is reading that, it's unlikely your supplier's meter is at fault. Only thing I can suggest is to walk around room by room looking for things turned on & seeing the change in the reading.


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## Pudsey_Bear (Sep 25, 2008)

One thing I've just remembered, and must surely have some impact is that we have 252 volts coming into the house, but I'm not sure if this makes things more or less expensive to run.

Kev.


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## SpeedyDux (Jul 13, 2007)

Kev, it struck me that maybe your electric installation needs a thorough check by a qualified electrician.

In my last house I had a mysterious electrical problem which caused the little disk (pre-digital meter) to keep spinning rapidly even when every appliance and light in the house was off. 

It turned out there was a 240 volt spur cable in the basement under the wall plaster that had an old nail right through it. A previous owner's DIY error years ago which miraculously somehow missed the core of the cable. The cable insulation had gradually broken down to the point where there was now a minor short circuit that was getting worse but not quite bad enough to trip the circuit breaker! 

SD


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## Pudsey_Bear (Sep 25, 2008)

Thanks SD,

I bet that nail got a bit warm.


Kev.


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## safariboy (May 1, 2005)

I have one of these Maplin monitors and get these figs:

Computer unplugged 3W
Start-up and running 30-40W
Charging the battery 68W

Sleep 12W
Hibernate 10W

None would come anywhere near the 1.25A on the power supply even at 100V.
Two suggestions: either to allow for a power surge when you switch on or something to do with wattless current a topic that is only discussed between consenting adults.
When I worked at a school we did have a problem with a trolly of laptop computers that threw the trips when plugged in to charge and that seemed to be to do with a surge on switching on.


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## zappy61 (May 1, 2005)

Get yourself a wireless energy monitor (I have an owl from Mail on Sunday on offer at a about a fiver). You can see what appliances are taking at any one time by switching them off and seeing the difference. Fridges and freezers are on 24 hours so if they are inefficient they can take a lot of the daily total. How many KWh do use in a day on average? mine is about 12/14 even without anything on (when away) the freezers and fridge take about 5KWh per day! I cut my electricity down by about 25% by not using the immersion heater for hot water, I installed a systems condensing boiler (saved 15/20% on gas) which I use for hot water. I regularly monitor both gas and electricity my annual consumptions are aprox 5000KWh electricity and 19000KWh Gas per annum. Great to know these figures when accosted by the energy sellers.

Graham


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## Rosbotham (May 4, 2008)

Good suggestion Graham, but Kev's got an Efergy...that is a wireless monitor of the type you recommend.


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## Pudsey_Bear (Sep 25, 2008)

I'm compiling a spreadsheet, then I'm going around room by room, and writing down every single item, both on standby and in use.

Kev.


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## safariboy (May 1, 2005)

Kev_n_Liz said:


> I'm compiling a spreadsheet, then I'm going around room by room, and writing down every single item, both on standby and in use.
> 
> Kev.


You might find this book by a Cambridge engineer interesting. It is hard going in places but he tries to look at energy conservation in an objective way:

http://www.withouthotair.com/

It is available as an internet download but I think that he is now selling it.


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## Pudsey_Bear (Sep 25, 2008)

I've got the pdf "making a difference" is that the one you meant, looks like heavy going as you say.

Kev.


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