Do I have this correct?

Theoretically, 250 watt HPS uses as much energy as about 6, 42 watt, CFLs?

How many lumens does a 250w HPS give off compared to 6, 42w CFLs? The same?

yes, but lumens to my limited knowledge are not always equal as far as their power goes. There was a nice stickey on the top of one of these pages that has a good article about lighting and lumens. It ended up in a comercial of some sorts about a new type of light, but still it had a nice primer on it, and was much food for thought. HOpe this gets your mind crankin until a pro comes in here and gives you more useful info.

the hps will have about 1.5 times the lumens of the cfl's

A 250 watt HPS light puts out something like 33,000 lumen's, so no 6 42 watt cfl's don't even measure up at all.
One 42w cfl put's out about 2800 lumen's.

Plants don't use lumens.

i believe a 250 hps puts out around 25,000 ish lumens... not exactly sure... u coulda found out with 30 seconds and google.... and yes it use's the same amount of energy... but as for the lumens... it will put out a good deal more..... the bigger the hps the more efficient it is.... as for cfls... they will work fine... ive heard that cfls lumens do not stack so keep them evenly spread out so u can get the most out of them.... in my opinion hps is better then cfls

Compare lights by wattage. 250w HPS compared to 250w of CFL light. The HPS will use the exact same amount of electricity, and will be FAR more effective in growing weed. Make sure you veg with some CFL's too though, plants need the cool light in veg. But for flowering, CFL's dont even compare to an HPS.

a 250 mh blows away fluoros. i have both, go with mh or hps and watch how happy they become

Of course... since plants don't use lumens and most manufacturers don't list PAR.... you just never know. I'd take the HPS over CFLs 99.9% of the time.

I'm just wondering, so that if I do get an HPS, I don't want a huge jump in the electricity usage because my landlord pays the bill and he might come investigate or something. You never know.

If you are worried about the landlord investigating then I'd say don't grow. Probably a better idea not to anyway since he can walk in whenever he wants and look at anything he wants since it is his property.

Most light fixtures in a normal house hold 2 to 3 incandescent bulbs and most people use 100 watt bulbs. If you left your living room light on all day would you be worried about being investigated.

People get intimidated by HID lighting because of how bright it is, they think it is somekind of thermo nuclear reaction going on inside the bulb and the current must be a straight short to ground, but in reality they are just like have a couple normal bulbs on. They don't put off intense heat like everyone thinks either. I used to be intimidated by them too, but it has been so long ago I can't remember so I take a lot for granted.

la9 said:

If you are worried about the landlord investigating then I'd say don't grow. Probably a better idea not to anyway since he can walk in whenever he wants and look at anything he wants since it is his property.
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Landlords are prohibited by law from entering the home of a tennant without a certain amount of notice. There was a thread on here a few months ago where a guy was busted when his landlord stopped by unannounced and discovered his grow. The landlord reported it to the cops, who seized everything and charged him. He had the case dropped because of the landlords actions. The state even returned his HPS lamp.

FootballFirst said:

Theoretically, 250 watt HPS uses as much energy as about 6, 42 watt, CFLs?

How many lumens does a 250w HPS give off compared to 6, 42w CFLs? The same?

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Just get a light meter. You need to know how many lumens at how many feet away from the plant canopy. 1 thousand watt hps puts out 140,000 lumens at 1 foot away but at 4 ft away its only 9,999. You can only keep the plants so close to the light so the initial output isn't what you want. The goal is to give the plants 10,000 lumens at their canopy.

FootballFirst said:

I'm just wondering, so that if I do get an HPS, I don't want a huge jump in the electricity usage because my landlord pays the bill and he might come investigate or something. You never know.

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That's why they list watts. Just go by that and it's all good. My pc power supply uses 500 watts.