Temperature Question

JohnCee said:

I'm running a 315w cmh with a cooling lens kit installed, and a mars 300w for supplemental lighting in my 4'x4'x6' flowering room. I'm getting temperatures of 84F-86F inside of my room, and temperatures of 72F-75F in my basement. I've been trying my hardest to match the temperatures in my basement, however, I cannot seem to accomplish that. I have even tried leaving the door open to my flowering room and placing a fan in the door to pull in the basement air and the temperature only got to 81F at the lowest. I'm using a 334 cfm can-fan max to pull air out of my room through my light fixture hood.

Would you guys think it's possible to reach my basement temperatures without any kind of a/c unit running?

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BMWEATER said:

Is the grow room inside the basement?

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ipeeinpools said:

Where are you dumping the exhausted air?

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JohnCee said:

Yes.



Right back into the basement. I have a thermometer at my air intake/exhaust and both are showing the average basement temperatures, 72F-75F. I would have just vent out exhausted air right outside, had it actually been a problem releasing it back into the basement, however since there is no temperature increase I do not see the harm. It has to be that the bulb is still getting too hot and not get exhausted out, right? Because even when leaving my grow room door open I cannot match the average basement temperatures.

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Enigma said:

An intake fan and filter would help greatly.

Also, are you measuring air temps accurately or is the light shining on your temperature sensor? Radiant heat from the lamp will give you a different temperature than the air.

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ipeeinpools said:

Your flower room is the main source of heat so it will never drop to match the rest of the basement if you still dump the hot air into the basement. where is your intake coming from? I would figure out a place to dump that hot air. my basement is split in half by a wall and I grow on one side, dump my air on the other. I didn't used to but I was having the same heating issues, and when I got that hot air out of that side of the basement, my temps dropped.

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JohnCee said:

I do use an intake fan, however, it's just a random $35 fan from lowes.. probably 150-250 cfms. I don't think a larger intake fan would help since I have tried leaving the grow room door open with a box fan propped up into to move the basement air into the room. I learned about how to properly measure the air temperature a couple of days ago, and since that time I have always made sure to leave my meters out of the light source.



I'm using the basement for my air intake source since it's the coolest area in my house. I have a thermometer suspended in the air where my flowering room exhausts the air back into the basement, and it's about the same as the average basement temperatures, 72F-75F. I already have a slight negative pressure inside of my room, because when the door is within 1-2 inches it will continue closing all the way itself.

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ipeeinpools said:

so your air cooling your CMH? where is that intake coming from?

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Enigma said:

Have you tried removing the LED panel?

Do you have a circulating fan to push the hot air up and away from the canopy?

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JohnCee said:

I have one end of my fixture hooked up to exhaust out of the flowering room, and the other end of the fixture is open and acts like the exhaust for the room. Basically, my flowering room air is being sucked up through the light fixture and out of the room. I probably should have mentioned that it wasn't a completely closed air cooling system for the CMH.

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Enigma said:

I don't doubt the HID is producing more heat than the LED, I just wondered if the two combined would put the temps over the top or not.

Does the CMH have a removable ballast?

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ipeeinpools said:

Ah ok, so I think therein lies the problem. Your cooling your CMH with hot air essential which in turn is not cooling your CMH. Your doing the same thing I was when I set my 10x10 up, I was pulling the tent air through my hoods and dumping into the basement. I would turn your light into its own duct system, pull from the coldest place you can. If you can I'd figure out how to dump that hot air somewhere other than the basement. At night here it gets nice and cool so I pull the air in through my window. then you can set up another exhaust at the top of your tent, and use passive intake at the bottom.

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Enigma said:

Where is the RH?

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Budley Doright said:

It will always be hotter in the room but the more air exchanged the closer it will get, upgrading the exhaust fan that just does the room will help but if you leaving the door open and a fan blowing in the air it may not help much. Your floor is concrete I assume? This is basically a heat sink but you've lost that effect in the room somewhat as well. Doubt it will get much better than what you have without cooling.

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JohnCee said:

I basically rigged up my air intake and exhaust to run through my light fixture, which means that my actual room is not receiving any kind of ventilation, with the exception of a couple of fans moving air around. With the actual room air not being exchanged, of course except for the air random air leaks that exist in the structure of the room, it should in theory be easier to cool the room, correct?

How often do you think a small a/c unit would be kicking on and off had I set the a/c temperature to 77F? I really only need a 7-10 degree difference in my 4'x4'x6' room, and since the air is not really exchanged it should remain cooler in the room, of course until the light warms it back up eventually. I'm just trying to gauge how often I'll have to be running an a/c unit throughout the 12 hours the light is on during the day.

I never wanted to run an a/c unit, but it doesn't look like I have many other options here. Considering my ventilation holes went to running air cooling for my light fixture, would it be a bad idea just to throw a small a/c unit into the actual room, or would that running be harder to cool the room down?

Edit: I'm not sure if it's noteworthy, however, I am able to place my hand ~7 inches under my light fixture and still feel a bit of heat coming directly down, is that bad?

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JohnCee said:

I basically rigged up my air intake and exhaust to run through my light fixture, which means that my actual room is not receiving any kind of ventilation, with the exception of a couple of fans moving air around. With the actual room air not being exchanged, of course except for the air random air leaks that exist in the structure of the room, it should in theory be easier to cool the room, correct?

How often do you think a small a/c unit would be kicking on and off had I set the a/c temperature to 77F? I really only need a 7-10 degree difference in my 4'x4'x6' room, and since the air is not really exchanged it should remain cooler in the room, of course until the light warms it back up eventually. I'm just trying to gauge how often I'll have to be running an a/c unit throughout the 12 hours the light is on during the day.

I never wanted to run an a/c unit, but it doesn't look like I have many other options here. Considering my ventilation holes went to running air cooling for my light fixture, would it be a bad idea just to throw a small a/c unit into the actual room, or would that running be harder to cool the room down?

Edit: I'm not sure if it's noteworthy, however, I am able to place my hand ~7 inches under my light fixture and still feel a bit of heat coming directly down, is that bad?

Click to expand...