How to calculate the electrical cost of running a tank.

The question is often posed about the actual rand value on running a fish tank. So here is a simple explanation of how to calculate it.

You will need a few things first:

• The price per unit that you pay for electricity. Each area is different, and in some area's, the unit price actually increases and decreases seasonally. You can get this price off your electricity bill. For purpose of this example, my unit price is 98c per unit.
• The wattage rate on the equipment you are calculating.

One unit of electricity, (@98c) is equal to 1kW of electricity.
The wattage rating on your equipment (eg a 300w heater) means that the heater uses 300watts of power per hour.

The maths guys have worked this out already.

300w = 0.3kW. (remember KILOwatt means 1000)

But let's make this for dummies....

1. Take the wattage of the equipment and divide that by 1000. (300w / 1000 = 0.3kW)
2. Take this result and multiply it by your electrical unit price (0.3kW x 98c = R0.294)
3. This is the actual cost of running this equipment for one hour! (i.e. 29.4cents)
4. You can now multiply this by the number of hours per day, and then the number of days per month to give you a MONTHLY cost.

Let's assume the following in a tank:

100W of lighting for 8 hours a day.
100/1000 = 0.1
0.1 x 0.98 x 8 x 31
=R 24.304 per month

60watt filter for 24 hours a day
60/1000 = 0.06
0.06 x 0.98 x 24 x 31
=R 43.7472 per month

150W heater on and off randomly for an assumed average of 6 hours a day
150/1000 = 0.15
0.15 x 0.98 x 6 x 31
=R 27.342 per month

5W Airpump on 24 hours a day
5/1000 = 0.005
0.005 x 0.98 x 24 x 31
= R 3.6456 per month


Thus the total cost of this tank, assuming the hours as indicated above would be: R 99.04 per month! (Just keep in mind this is Ex. VAT as my unit price is R0.98 ex vat)

Just a side note for those of you who are "green"
For those of you who have seen a pattern here... you can actually now calculate the cost of any electrical item in your house. That 2500w tumble dryer that you have on for 90mins costs you R3.675. Doesn't sound like a lot does it? How many times do you use the tumble dryer? Or wait... that 2500w DISHWASHER you use 2 times a day for a 2 hour cycle?
That 1500w oil heater you leave on 24/7 in winter... costs you R1093.68 per month!
Now go and calculate the cost to leave a tv, a pc or a radio on... all which are MINIMAL wattages. Did you know that it sometimes uses MORE electricity to power up certain appliances than if you were to just leave them running? Go work out your lighting costs.
You will be surprised that many things that we are fussy about turning off all the time are in actual fact items of extremely low electricity consumption. Think about it- 98cents, i.e 1000 watts of power, will run a 7w energy saving globe for 142 hours! But that same 98 cents will run a tumble dryer for literally a couple of minutes.

The items that push your electricity bill up is not lights, tv's, fish tanks (barring the heater). It's anything that creates HEAT. This is washing machines set on hot, tumble dryers, dishwashers, kettles, microwaves, ovens, heaters.

A standard 3 bedroom house with underfloor heating in living room, bedrooms and main en suite has on average 12-15kW of heating pads. If ALL underfloor heating pads are on 24/7 you are looking at about R 9,000.00 per month.

Now you get a small grasp as to why government building regulations are moving towards banning underfloor heating, insisting on solar water heating, (or heatpump or gas) and gas cooking.

 

thanks i had a conversation with my landlord yesterday on the cost of running a tank
i will forward him this right now to put his mind at ease

 

Thanks for this riteup @Zoom. This question keep lots of aquarists away from planted tanks I am sure.

 

Great write up and examples @Zoom, sure lots of TASA members will benefit from this

 

I finally got to use my calculator.
My 100 litre aquarium =R 59,93974 per month.
(the aquarium heater is the most expensive to run: R54.684 per month)

 

Great article. thanks although not sure that my heaters are on for 6h/day im thinking less, especially in summer.

 

Now I can show my dad that my tank uses less $$ than my PC.

 

Id rather skip all this cuz im running so many stuff

 

Good job zoom - makes mostly sense as a mathematical exercise ... but to get the true cost you need to measure the power consumption used over a period of time. Problem with using indicated wattage on appliance is that it is not always 100% accurate or taken at load. Funny things happen - pumps can actually use more power under load / age. Light you need to include the loss on the ballast and so the list goes on, but as a guide this is a very good start.

Truth is it is actually cheap to run a single tank or two and as hobbies go, the running cost of your tank is probably a fraction of the rest of the initial cost and ongoing running expenses.

BTW a 60W pump ... might be worth investing in green pumps - maybe one of the things that people should consider when they look at buying kit, energy efficient equipment might be worth the extra cents.

Later Ferdie

 

How does one tell whether a pump is green? Fridges have A+ etc ratings, what does one go by with a pump? Flow/h @ 1m head per Watt?

 

No rating that I know .. but in general you can compare l/h + head and get a feeling about the power used. New generation filtration typical advertise that they are greener than the old version. Typically your brand names are better than the cheap clones - but this is not always the case.

Eheim, JBL I have found to be better than most but at a price.

 

Thanks Ferdie. I actually thumb sucked the wattages.

ANd yes, you are totally correct on loading and age of equipment... I just needed to give a general indication.

 

OK so if math is not the way to go, builders have some ellies imported efergy kit that is affordable ... This R220 unit will "track" your cost. It needs some time to get to the full year values etc (I am aiming for about R3800 per year) this plug covers 90% of the fish room plus PC. This is my lights + pumps + PC with not heaters.



Form efergy.com

• New LCD with more and clearer information
• Information displayed: in time related, cost related, energy parameter
• Up to 7 energy parameters displayed (W, kWh, V, A, Hz, PF %, Max)
• Select up to two tariffs
• Check your cost by day, by year and so far
• Up to 5 different currencies available (£, €, $, Kr, R)
• If the EMS is on AC power then the screen is always ON
• If no appliance is connected the EMS will not start counting
• When battery powered the screen shuts off after 30 seconds of inactivity

I am intrigued enough that I might get an energy hub from them that connects to your PC .. or not, I see they also have on the has a current senor with a 433Mhz transmitter - should be able to hack that onto my andrino.

@Razer2007 - I did the check my PC draws exactly the same as the fishroom - 13 tanks with lights and pumps + the outside circulating pumps

Later Ferdie

 

Actually like this little unit - in the past 24 hours I consumed 6.6KW hours making it just over R6 a day or R2190 a year ... now this is without heaters.

 

Cool little device.

 

So almost a year of using the device ....



Not to bad if you think about the winter heaters ... then again the extra insulation did help this year.

Later Ferdie

 

Working mine at 0.65c a KWh I use R755.80 a month taking an average of heaters on for 12 hours a day as winter they run almost 24 hours a day. Not a happy figure.

 

Yeap that is why I only run minimal heater in winter and even then they are set to 20 degrees or 18 depending on the tank.

At the moment no heaters are running and tank temps are 22 - 24.

Later Ferdie

 

Try running minimal heaters for example 300 watt in 620l tank, 550watt in 720l tank with 80l sump and 600 watt in 1000l tank and a few smaller tanks. Better start turning temps down

 

The other bugger with temps is surface movement .. so cold air being pumped into the water column almost instantly costs you money in heating. Not to mention sumps that are not insulated and covered etc...