Sorry if this is a typical noob question. My friend and I were discussing what will cost more to run, we are using the same setups except for the lighting, I am using 600W of CFL's, (actual, not incandescent equivalent) he is using a 400W HPS/MH. Say theoretically we were to run the exact same schedule, what would cost more?

Sense you are using actual 600w CFL's and your friend is using 400w HPS/ MH. What you want look at is the actual or real watts, the higher your watts the power you will use. It's a standard measure for any electric device

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Grow your own, Keep on smokin!

Yep, 600 watts vs 400w is all the math involved.

A watt is a watt, is a watt, is a watt, etc.

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Charlie

im running one 300w dual spectrum CFL enviro light, the dude in the shop rekons that it would cost about £2 a week to run(about $4)

You are using 50% more watts than your friend, and he is still getting almost the same lumens as you. To calculate usage convert your watts to kwatts. 600w=0.6kw. Multiply by the number of hours a day your lights will run. This will give you kwhrs. You can look on your last electricity bill and find a rate in kwhrs. Multiply this buy your daily usage of kwh's and you will get your daily costs. It will be interesing to see how the bud compares. Are you using the same clones, nutes etc?

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My six plants are 100% legal. Thanks prop 215

Yes, same nutes and clones of his, the setups are slightly different but not much, I have a setup made of 5 gallon buckets, his is in a single rubbermade container with multiple baskets in the lid.