Closet grow room too hot, would this setup work?

Background: I have a small closet grow room going which is currently serving as the space where my plant is flowering. My lighting setup is a 250w hps with a basic wing hood/reflector that is hovering 15" above the top of my plant (too far I know). When the lights are off the closet temp hovers at around 79 while the living room air right outside is a/c and maintains at around 77-78 most of the time.

Problem: When running the lights the closet temp jumps up to around 90 which I think is way too hot. As for ventilation all I have right now is a small fan blowing air from the back of the closet toward the door. The door is a sliding door and I keep it cracked open to let the air blow out.

Proposed Solution: What would happen if I installed an inline fan at the top of my closet and paired it with an air-cooled reflector setup in the following way:

6" inline fan --------- > air-cooled reflector/lamp -----------> outside of closet

the -------> refers to 6" duct tubing

I think this could help get the hot air from inside the closet to the outside. As for getting cooler air into the closet I guess I could run the same setup with a second inline fan taking air from the living room and pushing it into the closet. However, would I really need an intake system as long as my exhaust system works? As stated earlier, the temp inside the closet when the lights are off are around 79 which is only slightly warmer than the living room temp. If I could keep the room the same temp or a few degrees warmer when the lights are on I would be great with that. Thanks for any help!

Exchanging the air is the main thing. Its a pity you cannot drill a hole into the roof cavity as that is the best place to send the hot air. The other issue you will have to deal with is smell, it may not be an issue now but it will be.

It may be better just to evacuate the room itself rather than the light, but if you do go with the aircooled reflector, it pays to 'push' the air through the aircooled light rather than pull, mainly for the longevity of your fan.

Another way is to just evacuate the air from the room in order to drop the overall temperature of the room, and then focus a fan on the bulb/top of your plants.

So if I just had an inline fan in the closet with ducting going to the outside I could probably achieve a similar reduction in temps without the air-cooled reflector? I would then position my regular fan blowing toward the bulb/top of my plant.

My goal is to shave off about 10 degrees while being able to bring the lights a little lower to about 8-9" from the top of the plant.

Jonus said:

Exchanging the air is the main thing. Its a pity you cannot drill a hole into the roof cavity as that is the best place to send the hot air. The other issue you will have to deal with is smell, it may not be an issue now but it will be.

It may be better just to evacuate the room itself rather than the light, but if you do go with the aircooled reflector, it pays to 'push' the air through the aircooled light rather than pull, mainly for the longevity of your fan.

Another way is to just evacuate the air from the room in order to drop the overall temperature of the room, and then focus a fan on the bulb/top of your plants.

Click to expand...

It is something you can try...before you buy. If it works in your setup then no need to fork out for a cooled hood. I am running 2 x 400w in my closet and have a 100mm fan/filter blowing into the ceiling cavity. I also have a hole in the floor with a nylon stocking covering it to keep the bugs out. Air is leeched in through there during winter months, and I use another 100mm fan to bring air in via that hole, during summer months.

The three issues surrounding heat are, the room temperature once the room has warmed up, the direct ambient heat on the tops of your plants from the bulb itself, and temps when lights are out. Drawing the air out of the grow room, and even better, out of the house or into the ceiling, will keep the air temperature down. Having a fan on the tops of your plants and on the bulb will keep the direct heat on your plants down and allow you to bring the light closer.

hey bucks, about a year ago i installed a 6 inch inline fan that sits right above my light and pulls the air strait into my attic it helps a little that my walk in closet has its own a/c vent, but i didnt put any thought into when i turn my a/c off. so i think this winter when my a/c is off and the windows are open im going to sit a booster fan by the window and run some duct all the way to my closet so it can get some fresh cooler air

Thanks for the great info! I think I'm just going to have to rethink the closet project now as I didn't prepare proper ventilation/cooling beforehand. The closet location and setup/size is definitely not conducive to any real legit venting. Atleast I think I understand now what needs to be done for future grows. Thanks for the advice.

Last night I had to swap the T5 flo in for the hps as the temps actually got up to 95-96. The T5 brought it back down to below 90 but geez this is not a decent setup at all for flowering. I'm pretty much stuck now.. I guess I'll just ride this plant to the end and see what happens, then start over again.

i would cut 2 6 inch holes in the ceiling and i would put 2 inline fans.. one exhaust and one intake... the exhaust i would have hooked up to ur light... and then intake should have a long6 inch ducting tube go down to the bottom of the room and blow cool air from outside to bottom of room and that would help exhaust all the hot air..

then when it comes time to move or stop growing you get a piece of sting with a pencil or something on one end and place the side without a pencil through a small hole in a piece of cardboard big enought to cover the hole... ( the cardboard should cover hole with pencil on the top side... and the sting just hanging down so u can pull it down snug as u put that putty stuff for holes in walls... and ur good no one knows the diff until its to late...

I have a 3x4x8 closet w/ 400W HPS. Same heat problem and I have a 4" fan in the ceiling going to the attic. The mites love it. I was thinking of either getting a second clip fan for the tops of the plants (bottom 2' of the room stays about 65-70 and I have a small fan on the floor), or get an air cooled hood. If I went with the air cooled hood I was going to put a 400W MH and a 400W HPS so that I could get more of the light spectrum. Maybe even go with 2x 250W to keep temps down a bit. Guy at the hydro store said that putting a booster in the line after the fan would probably do the trick. Any thoughts?