Lights needed for a 12'x12'

If i went with 1000 dehps how many lights would I need to cover a 12 foot by 12 foot area?
I am strongly considering 9 hlg 550s I dont care about the argument of if hps is better than led just wanna know how many light fixtures would be optimal, electric savings is a big need for me to avoid red flags so if I'm using 4500w on 9 hlg 550 I dont wanna use 9000w on 9 dehps

nathanpunk said:

If i went with 1000 dehps how many lights would I need to cover a 12 foot by 12 foot area?

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4

I am not a lighting expert.....even after 7 years of growing, but have faced the same lighting question several times.

One of the deciding factors I took into consideration were how high will I be hanging the lights?

Another is the availability of sufficient electrical amperage? Should I go with 110v or 240v?

Of the now four grow rooms I've built, I've never had more than 7' of height. I opted to go with more 600w lights in smaller hoods than less 1000w in XXXL hoods. One of my last grow rooms were 12'x13' and ran six HPS and two 400w MH and was able to maintain 25 plants in a perpetual grow.

I'm in the process of building my last (I hope) flower room and this time I'll be running four 600w HPS and two 315 CMH as this room is only 9'x13'. My focus isn't about yield or big plant counts, but more about growing top strains. I'll probably go with around 12-14 plants. My rule of thumb is 4 plants per 600w. It's worked for me as a starting point.

9 1000w DE or 25 CMH.

Have you considered you walkways and tool storage areas fan areas and extraction methods? If you have you wouldn't need those areas covered directly by lighting and could use less while being more organized.

9 HLG 550's would be spot on for a 12'x12'

Carolina Dream'n said:

9 1000w DE or 25 CMH.

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WOW! I'm sure that would certainly light a 12x12 area.....but cannot imagine the heat one would have to deal with using that many lights.....let alone the amp-draw one has to accommodate to run all that.

For a 12x12 you want 7200 - 9000 watts of HPS. Many DE lights have a rectangular pattern though.

lilroach said:

WOW! I'm sure that would certainly light a 12x12 area.....but cannot imagine the heat one would have to deal with using that many lights.....let alone the amp-draw one has to accommodate to run all that.

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lol yeah I hear that. My two flowering rooms are on a flip, each has about 10kW and a 4 ton AC. With one flowering room and veg room running I pull about 80 amps on both legs.

Renfro said:

lol yeah I hear that. My two flowering rooms are on a flip, each has about 10kW and a 4 ton AC. With one flowering room and veg room running I pull about 80 amps on both legs.

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I did the mini-split to counter the heat thing, along with running CO2......about 25% more yield....but man, the power bill was a killer.....that and I wasn't happy working in a 95 degree room.

lilroach said:

I wasn't happy working in a 95 degree room

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Damn that is hot. I never go above 90 with CO2. 90 is when my high temp cutoffs kick in to kill 3600 watts of side lighting.

As to the OP, with HPS 50 - 62.5 watts per square foot is a good range for flower. The higher figure for a CO2 enriched grow. 40 watts per square foot is adequate for veg hoever I generally use CMH or MH for veg as the plants get pretty stretchy under HPS.

As to the LED idea, that will save a ton of electricity, even your cooling bill will go down. Another option is CMH. They run a little cooler than HPS and 35 - 40 watts per square foot is good for flower.

What is your ceiling height? If you got the height I’d say 6 de hps will do it. That’s giving each light a 4x6 coverage area. That is slightly over the recommended coverage area but close enough it should be good.

If you have 8 foot ceilings or less I would not go with de hps. I have 11 ft ceilings and with any less than that I’d be worried about it as the top of my head gets pretty warm in there.

For short ceilings I would use a 315 cmh spaced 1 per 3x3. So that would be 16 of em for the whole room. Initial investment is a little higher (prob still cheaper than led) but I’ve never seen any other light put out the quality the cmh does. The numbers can be really good with cmh too you just got to learn how deep you can penetrate and get good at taking everything else off.

lilroach said:

WOW! I'm sure that would certainly light a 12x12 area.....but cannot imagine the heat one would have to deal with using that many lights.....let alone the amp-draw one has to accommodate to run all that.

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6000btu per 1000watts of light. I’d put a 4-5 ton ac in. You gonna pull around 35-45 amps on 220v for lights. Another 40-50 amp 220v for ac. And 20 amps at max for dehumidifier and room fans. Power usage is part of growing, can’t get around it.

I would say 10 HLG 550s is the minimum for 144sqft, but if you are supplementing with CO2, you're going to want more light than that even. I am currently building out a small warehouse, and in order to cut costs, we are ordering the equivalent of the HLG 550 from Kingbrite on Alibaba. They are $300 each and they include everything, ratchet hangers, etc.

With shipping, it came to $340 per fixture.

Total grow area...
12ft × 12ft = 144ft

Random data...
High end LED = 2.5μmol/J
HPS/CMH = 2.0μmol/J

HID is hung higher and has uneven distribution, so I'd say at least 8× 1000W DE total or 55.5W/ft2. I used to be ~62.5W/ft2, 3kW per 48ft2.



550s needed for 144ft2...
144ft2 × 35W/ft2 = 5,040W
5,040 ÷ 480W = 10.5

The hlg 550 is rated at 480W. Most people say 35W/ft2 with effecienct LED. I'd say closer to (10) 550s would be good for a 12×12.

Effeciency difference...
8000W ÷ 4800W = 1.66

If you went the HLG route or highly effecient LED route, you'd save maybe ~70%+ on your electric? 66% immediate savings in just the effeciency difference alone, plus less AC ect.