1000W HPS Bulb with lowest heat output

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CBD123THC

Member
Has anybody noticed that specific brands or types of HPS bulbs put out less heat than others?

I'm running the following in a 3' x 3' x 6.5' tent (Exact measurements are: 39" x 39" x 79") with a 315 CFM exhaust fan and passive intake. I'm just using the mesh intake vent at the bottom of the tent, seems to be plenty of airflow and not too much negative pressure in the tent but good airflow out of the tent.

Veg:
1000 Watt GrowBright - Metal Halide Conversion Lamp (cheap bulb) - 110,000 lumens
Tent Temperature: 77-83 degrees (outside temp 72-77 degrees, so about 5 degrees above the intake air temp)

Flowering:
1000 Watt Hortilux Super HPS Grow Lamp (higher end bulb I guess) - 145,000 lumens
Tent Temperature: 84-89 degrees (outside temp 72-77 degrees, so about 12 degrees above the intake air temp)

I know I know, most would probably say that 1000 Watts is overkill for this space - but I don't want to buy a new ballast. If I could go back, I'd purchase a 600W ballast for this tent instead of the 1000W. Anyways, my goal is to keep temps under 80 degrees at all times. As you can see the MH works fine as long as I keep the outside temperatures low enough, but I have decided that I'd like to use HPS during flowering.

So will switching to a cheaper/different brand/non-"super"/ 1000 W HPS bulb maybe lower my temps??? I'm fine with less lumens too if that's the issue here.

I also noticed that I can't really get my temp below 82 degrees with the HPS for whatever reason.
 
Lordhooha

Lordhooha

Well-Known Member
CBD123THC said:
Has anybody noticed that specific brands or types of HPS bulbs put out less heat than others?

I'm running the following in a 3' x 3' x 6.5' tent (Exact measurements are: 39" x 39" x 79") with a 315 CFM exhaust fan and passive intake. I'm just using the mesh intake vent at the bottom of the tent, seems to be plenty of airflow and not too much negative pressure in the tent but good airflow out of the tent.

Veg:
1000 Watt GrowBright - Metal Halide Conversion Lamp (cheap bulb) - 110,000 lumens
Tent Temperature: 77-83 degrees (outside temp 72-77 degrees, so about 5 degrees above the intake air temp)

Flowering:
1000 Watt Hortilux Super HPS Grow Lamp (higher end bulb I guess) - 145,000 lumens
Tent Temperature: 84-89 degrees (outside temp 72-77 degrees, so about 12 degrees above the intake air temp)

I know I know, most would probably say that 1000 Watts is overkill for this space - but I don't want to buy a new ballast. If I could go back, I'd purchase a 600W ballast for this tent instead of the 1000W. Anyways, my goal is to keep temps under 80 degrees at all times. As you can see the MH works fine as long as I keep the outside temperatures low enough, but I have decided that I'd like to use HPS during flowering.

So will switching to a cheaper/different brand/non-"super"/ 1000 W HPS bulb maybe lower my temps??? I'm fine with less lumens too if that's the issue here.

I also noticed that I can't really get my temp below 82 degrees with the HPS for whatever reason.
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What church said
 
C

CBD123THC

Member
Ryante55 said:
Are you measuring that with an empy tent?
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The temps I mentioned are from a mostly empty tent - actually I have one small house plant in there in about a 3 gallon plastic pot but that's it. No fans or anything else in there besides my air-cooled light and the inline exhaust fan running full blast.

I'm preparing for my second grow right now actually and these temps are pretty close to what I remember from my first grow - when I switched to the HPS I had heat issues but never before that.
 
R

Ryante55

Well-Known Member
CBD123THC said:
The temps I mentioned are from a mostly empty tent - actually I have one small house plant in there in about a 3 gallon plastic pot but that's it. No fans or anything else in there besides my air-cooled light and the inline exhaust fan running full blast.

I'm preparing for my second grow right now actually and these temps are pretty close to what I remember from my first grow - when I switched to the HPS I had heat issues but never before that.
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That's strange 1000w should be 1000w of heat only difference would be maybe right under the fixture the hps would read higher temp because of the ir
 
C

CBD123THC

Member
Cool so i don't know much about the heat and watts stuff but I believe you when you all say 1000 watts of bulb will produce 1000 watts of heat.

So even then, there must be something else going on here that plays a factor. Maybe the HPS bulb radiates the heat out further from the fixture or the MH can be more easily cooled by the exhaust fan based on the shape or something? Or maybe the ballast produces more of the heat with the conversion MH is installed instead of that heat coming off the bulb (ballast is outside the tent)? These are just random guesses I had but not based on any science that I know of

Anyways, it's there anybody out there that has had a similar experience with same watt bulbs of different brand or type having these types of temperature differences?
 
TreeFiddy350

TreeFiddy350

Well-Known Member
How do you keep your temps so low? I’m running 1000w mh in my 4x4x6.5 tent and temps shoot to like 85-90. I had to turn it down to 750w just to stay within range. How many fans and whatnot do you have?
 
Cappuchino

Cappuchino

Well-Known Member
CBD123THC said:
Cool so i don't know much about the heat and watts stuff but I believe you when you all say 1000 watts of bulb will produce 1000 watts of heat.
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In general, yes, 1000 watts of bulb will produce 1000 watts of heat. But you should take in count bulb efficiency: 100% efficient bulb will produce 100% light and no heat at all (for example FL and CFL produce much less heat then incandescent lamp). Also spectrum of the light take its place: HPS spectrum is more on the red side then MH and IR part of it heats up environment.
 
C

CBD123THC

Member
Cappuchino said:
In general, yes, 1000 watts of bulb will produce 1000 watts of heat. But you should take in count bulb efficiency: 100% efficient bulb will produce 100% light and no heat at all (for example FL and CFL produce much less heat then incandescent lamp). Also spectrum of the light take its place: HPS spectrum is more on the red side then MH and IR part of it heats up environment.
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That makes sense. So which brands of HPS bulbs are known to be most efficient? Or produce less heat? Here's a picture of the HPS I'm using. I wouldn't recommend this one for a small space like mine
 

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PrometheanLeaf

PrometheanLeaf

Well-Known Member
That hortilux bulb should be fine. Where is your intake and exhaust fans? And what is the ambient temp of the room the tent is in?

Make sure your exhaust goes out of your lung room right after passing through the a.c. hood and that the air movement in the tent is strong enough to evenly mix the air. That along with a decent exhaust fan changing out the air you should get a stable temperature differential. Say +8 degree f in the tent from the lung rooms ambient air. Then you need to set an a.c./heater in the lung room to correct what you need.

(Edit: wrote in a rush hope it makes sense)
 
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C

CBD123THC

Member
I only have the exhaust fan, it's attached directly to the hood and blowing through the hood (you can see my setup in one of the pics I posted above - exhaust fan on the top left and it's blue). The intake is just a passive intake and it's through that mesh screen at the bottom of the tent which you can also see in the pic.

(Edited to add a bit more detail about the exhaust fan - it's blue and located in the top left corner of the picture)
 
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C

CBD123THC

Member
PrometheanLeaf said:
That hortilux bulb should be fine. Where is your intake and exhaust fans? And what is the ambient temp of the room the tent is in?

Make sure your exhaust goes out of your lung room right after passing through the a.c. hood and that the air movement in the tent is strong enough to evenly mix the air. That along with a decent exhaust fan changing out the air you should get a stable temperature differential. Say +8 degree f in the tent from the lung rooms ambient air. Then you need to set an a.c./heater in the lung room to correct what you need.

(Edit: wrote in a rush hope it makes sense)
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The hortilux bulb is good, but I'm just wondering if I can get even slightly lower temps with the same setup and a different HPS bulb.

My ambient temperature is generally about 72 degrees, and so then my tent temperature stays at about 84-85 degrees. But for every degree that my ambient temp goes up, so does the temp in the tent.

I think my exhaust fan is pretty good, it moves 315 CFM but my tent is only about 70 cubic feet. So it should be replacing the air about 4 times per minute. The passive intake is at the bottom (where the coolest air hangs out I assume), and my heat dumps into a completely different room so the lung room does not heat up very much if at all.
 
C

CBD123THC

Member
Cappuchino said:
I personaly use COB LEDs due to stealth grow.
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Yea for sure, I did consider using those when I started but I liked what I read about HID so I went with that (should have gone with 600 Watts though). But I don't want to purchase any more equipment at this point! The most I'm willing to buy is a new 1K HPS bulb, and I might do that just to experiment. If I do I'll definitely post the results!

I'm going to do some topping and LST this time, because in my last grow I did not use any training techniques and I had a lot of vertical stretch after switching to HPS. The tops of the plants were lacking in smell, flavor and potency because they were too close to the light I think. I might be fine with this bulb if I just keep those babies lower to the ground and further away from the light.
 
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