# how to work out cost of an aquarium (electricity)



## aaronnorth (26 Sep 2008)

how do you work out how much 1w costs? or do you have to work in units in which case how do you do that?

i think there was a thread about it but i cant find it.


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## teg1203 (26 Sep 2008)

Hi Aaron,

Your electricity supplier will quote a price per unit of electricity which take the form of price per kilowatt hour. This means the cost of running a 1 kilowatt appliance for one hour e.g. a 2kilowatt fire would consume two units of electricity in one hour (2 x 1kw/hr) - if your supplier charges 10p per kw/hr then you would consume 20p worth of electricity.

A 1w appliance would take 1000 hours to consume 1kw/hr so the cost would be (using 10p unit as above) 10/1000 i.e. 0.01 of a penny each hour (or Â£0.0001 in pounds if you like).

Nuff said - if it's a 1w appliance forget about it, you probably use more power on a long cable run to an extension lead due to resistance in the copper wire. :? 

Tanks are a nightmare to cost as some elements are switched according to ambient conditions, e.g. solenoid on co2 (if you still switch by pH) and heater in a tank. There are devices out there that can calculate usage by plugging the appliance in. In the case of a tank I would suggest plugging an extension lead into the "calculator" and plugging everything else into the extension lead so that you can see total usage. If you want to determine usage of a single element fo the system simply remove it from the extension and calculate the difference over a set period of time.

It would be a interesting experiment though.

All the very - Tim


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## aaronnorth (27 Sep 2008)

thanks for the reply.. there was an question in PFK mag today lol, this is there calc:

wattage x hours it is on / 1000 x cost of unit.


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## teg1203 (27 Sep 2008)

aaronnorth said:
			
		

> thanks for the reply.. there was an question in PFK mag today lol, this is there calc:
> 
> wattage x hours it is on / 1000 x cost of unit.



Trouble with that answer is that if you apply it to a heater it tells you that a 100w heater uses 2.4kw/hrs per day - which is blatantly untrue (unless you keep your tank in a fridge :? ) So unless you're looking at worst case  it would be difficult to form an accurate answer.  

Incidentally the fridge would have to cool the water at a faster rate than the heater warmed it for the above statement to be true - I don't know how you would define rate of cooling in coparison to heating wattage.   

I'll get my coat.


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## bugs (27 Sep 2008)

PM me your email address if you're interested in a couple of Open Office spreadsheets - one to calculate heat loss of your tank (and therefore the running time of your heater) and the second to calculate component and total costs of running a tank based on your electricity costs.


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## aaronnorth (28 Sep 2008)

Ok,

my 180l has:

4w airpump
20w of filters
48w of lighting @ 10hours
200w of heating

lets do the 20w calc, it would take 500hrs to use a kw so it would be 10/ 500 = 0.02 of a pence (Â£0.0002)  

is that correct before i do any others? then i add them up and that is how much it costs a day?

Bugs, i'll PM you   

cheers everyone.


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## teg1203 (6 Oct 2008)

Hi all, I know this may be dead and buried by now but there is this

http://www.maplin.co.uk/Module.aspx?ModuleNo=38343&C=Newsletter&U=08P11-2&T=12779530

on the Maplin site at the moment and it is dirt cheap.

Hope it's of some use.

Cheers, Tim


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