SLUF681
Well-Known Member
There are many questions and comments on the forum and it's hard to find anything but opinions, not facts. I'm going to use some generic numbers in my formula. I am also going to assume a Power Factor of 1, as most of the time you won't know the power factor of the equipment you're using.
First off, we need to find out the wattage of the equipment. If your equipment is rated by the wattage, you're in luck! If not, let's find it...
Amps X Volts=watts
So, if your equipment (say a pump) is 3 amps (3A) and your house is 120V (some homes range from 110-120) your formula looks like this
3A X 120V=360 watts. Now you have your wattage to plug into the equation.
Now for the next part of the puzzle...
In order to find the cost of a piece of equipment, we need to know how much the power company is charging us PER KILOWATT HOUR. Don't know what a kilowatt hour is? You're in luck again! Quite simply, a kilowatt hour (kWh) is 1000 watts (a kilowatt) for a time period of 1 hour. So, if you are drawing 1000 watts, it will take you 1 hour to consume 1 kWh. 500 watts will take 2 hours to consume 1 kWh. 250 watts will take 4 hours and so on.
You can look on your provider's website and find the cost of 1 kWh. I'm going to use a price of $.10 per kWh as an example, because it makes my life really easy. That's a little high (less than a cent usually) but it makes for easy math!
Let's move forward, I'm starting to ramble.
Let's figure my metal halide consumption. I run 2 X 250 watt bulbs.
2 X 250= 500 watts. It takes 2 hours for my lights to consume 1 kWh. Assuming I run my lights 10 hours per day (I do), I consume 5 kWh per day. Assuming 30 days per month, my lights consume 150 kWh per month at $0.10 per kWh. That's $15 per month that my lights cost me, or $180 per year. But, as I said earlier, those numbers are a little high, due to the difference between my $0.10 per kWh figure and a real number around $0.9375. The total difference will be less than 10%.
Next, I want to figure a popular pump using a slightly different formula, the Mag7. The mag7 consumes 70W.
W X Hours/100=kWh
70W X 24 hours = 1680W. 1680/1000=1.68 kWh per day to run the pump, or $0.168 per day. $5.04/month, $60.48/year.
The second formula is definitely easier for anything that doesn't multiply to thousands easily (like my lights).
I hope I've explained that in a way that is easy to understand. If you have any questions, feel free to ask. I'll help where I can!
First off, we need to find out the wattage of the equipment. If your equipment is rated by the wattage, you're in luck! If not, let's find it...
Amps X Volts=watts
So, if your equipment (say a pump) is 3 amps (3A) and your house is 120V (some homes range from 110-120) your formula looks like this
3A X 120V=360 watts. Now you have your wattage to plug into the equation.
Now for the next part of the puzzle...
In order to find the cost of a piece of equipment, we need to know how much the power company is charging us PER KILOWATT HOUR. Don't know what a kilowatt hour is? You're in luck again! Quite simply, a kilowatt hour (kWh) is 1000 watts (a kilowatt) for a time period of 1 hour. So, if you are drawing 1000 watts, it will take you 1 hour to consume 1 kWh. 500 watts will take 2 hours to consume 1 kWh. 250 watts will take 4 hours and so on.
You can look on your provider's website and find the cost of 1 kWh. I'm going to use a price of $.10 per kWh as an example, because it makes my life really easy. That's a little high (less than a cent usually) but it makes for easy math!
Let's move forward, I'm starting to ramble.
Let's figure my metal halide consumption. I run 2 X 250 watt bulbs.
2 X 250= 500 watts. It takes 2 hours for my lights to consume 1 kWh. Assuming I run my lights 10 hours per day (I do), I consume 5 kWh per day. Assuming 30 days per month, my lights consume 150 kWh per month at $0.10 per kWh. That's $15 per month that my lights cost me, or $180 per year. But, as I said earlier, those numbers are a little high, due to the difference between my $0.10 per kWh figure and a real number around $0.9375. The total difference will be less than 10%.
Next, I want to figure a popular pump using a slightly different formula, the Mag7. The mag7 consumes 70W.
W X Hours/100=kWh
70W X 24 hours = 1680W. 1680/1000=1.68 kWh per day to run the pump, or $0.168 per day. $5.04/month, $60.48/year.
The second formula is definitely easier for anything that doesn't multiply to thousands easily (like my lights).
I hope I've explained that in a way that is easy to understand. If you have any questions, feel free to ask. I'll help where I can!
