1. ## Kilo watt hour

just out of interest i want to calculate how much it cost (electricity) to keep my computer running

i opened up my comp to see the power pack
on it it says
+5 21A
-5 0.5A
+12 8A
-12 0.5A
and it has a 210W rating

and Mercury charges 7.36c/kwh

anyone good with math out there
how much would it cost to run this computer for 8hrs

2. ## Re: Kilo watt hour

Hi Heni

Problem is your power supply will not be using the full 210 watts unless your box is fully loaded and if that was the case it would probably struggle, so 150-180 watts is probably closer to the mark. Add about 70 watts for your monitor and you have 250 watts or a quarter of a kilowatt.

Probable cost will be 16 to 20 cents per 8 hours.

Cheers

Billy 8-{)

3. ## Re: Kilo watt hour

As for the maths:

1 100W lightbulb uses .1kW per hour so:
10 100W lightbulbs use 1kW every hour (7.36c) or
1 100 W lightbulb uses 1kW in 10 hours (7.36c).

But as Billy says, computer power use is variable (unlike lightbulbs) so can only be worked out approximately.

4. ## Re: Kilo watt hour

7.36c per unit!! This is a good deal - are you sure? I guess this doesn't include the line charges - it should if you want an accurate answer. Most suppliers have an inclusive charge of around 15 c per unit (and don't forget GST)

5. ## Re: Kilo watt hour

you can go to http://www.mercury.co.nz and get all the options for power charges.

6. ## Re: Kilo watt hour

kW hours are simply the product of kW used by a device x hours.

simple.

7. ## Re: Kilo watt hour

It may be simple to you bazza, but it wasn't simple to heni, that's why he asked. Heather's example was simple and easy to understand.

Yours was no help at all as it presumes knowledge that the poster might not possess.

Cheers

Billy 8-{)

8. ## Re: Kilo watt hour

As Heather P was saying find out how many hours or part hours to get to one KiloWatt,

Say you whole computer needs 250 Watts, that is four hours to get to 1KW, then work out how many hours a year or how ever long you like, say you run your computer for 2000 hours a year (that's about how long we spend at work) so that needs 500 KW/hour of energy to run each year

If that is 10 cents a KW/H that will be \$50 to run each year

Just think of all those Fatal exception errors for just \$50.

9. ## Re: Kilo watt hour

Sorry forgot to answer the question.

> and it has a 210W rating
> and Mercury charges 7.36c/kwh
> how much would it cost to run this computer for 8hrs

With the above information
210 Watts for 8 hours = 1.68 kW/h
cost = 7.36 cents * 1.68 kW/h = 12.3648 Cents cost of power to run each day

Lets say just one Fatal Exception Error per eight hours, that's costs 12 Cents. Now were can you get so much unexpected enjoyment for just 12 Cents.

10. ## Re: Kilo watt hour

Back in 1994 (the Year of the Drought) I went through the exercise of working out what each item in the house used. As I remember toasters used quite a lot but only for a short period of time, TVs and computers were quite economic. The thing that really chewed through the power was the dryer. Used a drying rack that winter and really saved on the power.

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