Light footprint and cooling question

Hey guys just purchased 4 xtrasun de 1000w for a 12ftx12ftx12ft room to get things rolling, does anyone know how far I should keep these lights from the canopy? Theres not much documentation on these lights as far as I can find, I'm assuming to get a 4x4 footprint out of them and I plan on growing 4 plants under them, does all this sound logical?
Also does anyone have a mini split recommendation for this room?

12x12x12 room? You could run 9 1kW lights in there. You should plan the AC with expansion in mind. If you will ever run 9 lights in there I would go 4 ton, Midea makes a 4 ton unit thats wall or ceiling mount (I have 2) minisplitwarehouse.com has them.

Renfro said:

12x12x12 room? You could run 9 1kW lights in there. You should plan the AC with expansion in mind. If you will ever run 9 lights in there I would go 4 ton, Midea makes a 4 ton unit thats wall or ceiling mount (I have 2) minisplitwarehouse.com has them.

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Thanks for the info and I do plan on running 9 lights but I wanted to get started sooner than later so I got 4 for now and will find my other 5 lights later as they will require an electrical upgrade and thanks for the forward thinking on the split

I have a buddy with a similar room, he has 9 DE 1kW HPS in there. We put a Midea 4 Ton unit like mine and he is glad he did because he is now adding LED side lighting around the room. He grows big plants like me and adding side light turns that area into side canopy making big colas like the top canopy. We are putting the LED side lighting on a high temp shut off so if the AC can't keep up they will shut off for a while to let the room cool.

If you can swing it put a single zone 4 ton midea in there and have room for expansion. I wish they had sold the 5 ton unit when I bought mine I could use it. lol The Midea units are very good for the price. They will run down to 5 degrees outside, I have actually had mine down to 1 degree outside and still working. I run mine on a flip so they power up when the room powers up, they remember the setting and go to work after a two minute delay.

I have mine ceiling mounted in a basement off the floor joists using strut channel. I have the extra area in my room so that works for me. You can use it as a wall mount down by the floor and let it blow the air upwards and mix it with oscillating wall fans that blow under the lights and above the plants.

https://www.minisplitwarehouse.com/product/midea-48000-btu-18-seer-floor-ceiling-mount-mini-split-heat-pump-ac-dlclrah48aak-dlflfah48xak

A more expensive option is a multi zone unit with a 1 ton air handler up high on each wall. That would cost more and would have more potential for leaks with all those flare fittings. You also have 4 condensate drain lines to deal with. It would however provide very even cooling of the room. You could set the air handlers in a sequential mode so have two set to keep the room at say 76, then have one kick on if it hits 78, and the other kicks on at 80. That would be very energy efficient.

Don't forget to have a good dehumidifier. The AC will dehumidify some but if you live in an area with high humidity then you will need more dehumidification, especially when the lights are off and the AC isn't cooling a heat load. The cooler air will hold less water so as the air cools the RH% rises. A dehumidifier is very important unless you live in a region with low humidity and can just vent to drop RH% but even then in the winter you can only pull so much cold air in when the lights are off.

If you want to add a CO2 generator the extra cooling capacity is handy then too. Trust my, I know. lol

Once you get everything set and tuned you will be so happy. I used to run without AC, just using large blowers to bring in filtered air and only running one flowering room at night. Had some great runs but once I added the AC and CO2 generator things got a lot easier and yields went up, bud density went up, quality improved.

Anyways, I am babbling. Happy growing!

I appreciate all the info this grow will be an upgrade from a 4x8 grow so I'm hoping for great things this time around, I've learned a lot and keep learning every day so sometimes having an extra perspective helps keep things in track since there's so many factors to growing. I appreciate your input and will take serious consideration to it in this setup I am hoping for about 6-8 pounds with 4 lights

nathanpunk said:

I am hoping for about 6-8 pounds with 4 lights

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A very doable amount should things go well and your genetics are on point. A good grower should be able to pull 2 pounds a light given a good yielding strain.

So aim for 6 and if you hit 8 you will be happy. If you only get 6 you still did well but have room for improvement. Usually the first run tuning a room will be a little lighter. Once you get a few runs under your belt you should be pulling 2 pounds a light consistently. Just watch out for pests and mold / mildew. Those are the biggest bumps in the road for most growers. Be proactive and prevent instead of trying to correct a bad situation later.

Looking at the spec sheets for the latest midea 4 ton it seems they rate the low ambient at -13 F now! Nice. Mine were only 16 SEER now they have 17.8 SEER.

My buddy has his running on a Pebble WIFI controller so he can see the temps, change temps, set schedules for on and off all from his android anywhere he has internet access. It's pretty slick. @TintEastwood uses a similar type controller on his, Sensibo I believe.

Renfro said:

12x12x12 room? You could run 9 1kW lights in there. You should plan the AC with expansion in mind. If you will ever run 9 lights in there I would go 4 ton, Midea makes a 4 ton unit thats wall or ceiling mount (I have 2) minisplitwarehouse.com has them.

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I read somewhere (I think it was from you ) that this is the calculation:
1 x DE 1kW = 6000 BTU.
6.000 BTU = 0.5 ton.

So my calculations make 9 x DE 1Kw x 6.000 BTU = 54000 BTU = 4.5 ton.
How can be 4 ton be enough then?

I am no expert and by no means questioning your knowledge about this, but I try to understand the system for future shopping.

Keesje said:

I read somewhere (I think it was from you ) that this is the calculation:
1 x DE 1kW = 6000 BTU.
6.000 BTU = 0.5 ton.

So my calculations make 9 x DE 1Kw x 6.000 BTU = 54000 BTU = 4.5 ton.
How can be 4 ton be enough then?

I am no expert and by no means questioning your knowledge about this, but I try to understand the system for future shopping.

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Yeah the "California Rule" values 1kW DE Lights at 6k BTU/hr but I do think thats a really safe number.

I do know that my rooms are pretty much maxed out with 6 x 400 watt, 2 x 600 watt and 6 x 1kW DE. So I think a 4 ton can get 10kW done but thats probably about it.

I don't think anyone really has a solid number for heat produced by any light so we often use estimates that are a bit high.

Renfro said:

I don't think anyone really has a solid number for heat produced by any light so we often use estimates that are a bit high.

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Guess too high is always better.

So wouldn't a 5 ton for 9 DE kW 1 not be better?

There must be a calculation. I can't find it so far. All that I found was too complicated for me as well


@nathanpunk Did you not consider getting led?
With 9 x 600 Watt for your space you would probably have the same amount of light.
And the led produces less heat then other lamps. So another winner (just talking about heat)

Keesje said:

With 9 x 600 Watt for your space you would probably have the same amount of light.

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No, not hardly.

Keesje said:

So wouldn't a 5 ton for 9 DE kW 1 not be better?

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Always, especially if side lighting would be a future possibility.

Keesje said:

And the led produces less heat then other lamps. So another winner (just talking about heat)

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Good LED. Some of the cheapo ones make more heat than light I think. I am currently working on a LED light that would be a replacement for a DE HPS. It is my estimate that they will put off about 2750 BTU/hr each while keeping the same light intensity but with a more even light distribution from 12 cobs instead of one bulb. I am hoping to save about 1.5 tons of cooling and that will help me because my daytime 10kW flowering room is too much for my 4 ton when it's hot outside. Cost to build the fixture will be about 750 - 800.

Renfro said:

Good LED. Some of the cheapo ones make more heat than light I think. I am currently working on a LED light that would be a replacement for a DE HPS.

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I know to little about those DE lamps.

I do know that if you build yourself a nice led fixture with those Samsung strips, that you can replace a 1000Wat HPS with 500, 600 or 700 Watt led.

Keesje said:

I know to little about those DE lamps.

I do know that if you build yourself a nice led fixture with those Samsung strips, that you can replace a 1000Wat HPS with 500, 600 or 700 Watt led.

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The DE's put out more light but also more heat. They are awesome lights. I don't see 500 replacing a 1kW HPS without a little yield loss. 600 could get it done. Need more for the DE, so I am gonna be pushing 720 watts to the cobs.

Renfro said:

I don't see 500 replacing a 1kW HPS without a little yield loss.

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If you would run a lot of led on a low amperage, it can be done. But it would cost so much extra that it would be not very economical.
Again: I am no expert on lights (neither on AC's ) but this is what I have seen in growjournals.

This is the driver that comes on the Autocob

https://www.mouser.com/ProductDetail/MEAN-WELL/HBG-60-1050?qs=IL6XaBr%2B7X93z1FGeM7e6w==

The driver, chip holder, heatsink, proper COB (autocob is using a Citizen CLU-048-1812, not sure what generation) and some Arctic Silver is pretty much all you need.

As I understand from fellowgrowers the thing to do nowadays is using the 4 ft long led strips from Samsung.
But I am sure you looked into al of that already.

Sorry, that last post was for another thread. lol