Trying to solve a cooling problem! I'd appreciate any help...

Hi guys,

Long time lurker here, first time poster. I've had a grow room in a walk-in closet I have for around 3 years now, and have had reasonable success. I desperately want to improve my grow environment, but I'm having a frustrating time keeping my grow room cool.

I have two 600W HPS lamps in cool tubes in a walk-in closet that measures 6' X 5' X 8'. Air is drawn through a carbon filter that sits near the ceiling in a corner of the grow room with a 6" duct fan (334CFM), through a Y splitter, through the 2 cool tubes, through another splitter (to join the two ducts back together), and out the closet door into my bed room. I have a 5000BTU portable air conditioner that sits in the corner of the grow room as well. With this setup, my grow room regularly averages temperatures ranging from 80F to 85F.

I am getting ready to upgrade my grow room, and I would really like to modify my setup to keep temperatures down. I've attached diagrams of my current setup, and my proposed setup. I was thinking that I could put ducting through the wall of the grow room, into the next bedroom, and connect it to the window to draw outside air in to cool the lights, and then spit it back outside again. But, because I live in the south, the air temperature outdoors is usually in the eighties. So I'm not sure if this would even solve anything.

I've attached diagrams of my current setup, and my proposed setup. I'd appreciate any advice you guys could give me... I've been driving myself nuts over this. I'm considering switching to LED because of this issue, but the one I would want to replace my current 1200W would run me $1700. I'm not crazy about that idea. Really, all I want to do is get my temps down... and I feel like there has to be a way to do that without buying LEDs.

One more thing--I've ordered a water chiller for my system, and I plan to put it outside the grow room.

Have you considered adding another air conditioner?

I don't have enough room in the grow room to fit another. I think I've been convinced to just go LED. I'm going to run a 650W panel in the room, and use my duct fan to ventilate. With the addition of the chiller, I'm hoping this will drop temps substantially.

you'll be disappointed. 2 600's HPS will blow away a 650 led.

buy a bigger A/C. 8000 to 10000btu will get you in the 70s easy.

and one led wont cover a 5x6 either

If I where you I'd run a 6 inch duct fan for each light, your loosing a lot of cfm in the y section and also keeping the air to cool your lights seprate from the air in your grow room helps a lot too. Also are you just using the AC air as an intake? Do you have passive air intakes?

codayyy said:

If I where you I'd run a 6 inch duct fan for each light, your loosing a lot of cfm in the y section and also keeping the air to cool your lights seprate from the air in your grow room helps a lot too. Also are you just using the AC air as an intake? Do you have passive air intakes?

Click to expand...

I'd just look into along the lines of what this gentleman said. Put a 440 or close to it cfm fan filter on each tube and y them only at the exhaust point. Grab a 10 or 12k A/C. problem solved. Throw a swamp cooler in there for veg if your having humidity issues. Borrow an IR laser thermometer from someone you know or some tool rental place and see what the actual temp your plants are. I'm not an expert by any means but seeing as you actually have the ability to cool the room with A/C I feel like this problem can be solved fairly simply, and for a whole lot less than 1700 bucks mang

I'm actually a hvacr tech for a living and just by adding a larger AC might or might not solve your problems. By adding a larger AC you are just adding more cooling capacity to the room so the AC might cool the room faster but cycle on and off even more because you only want the room so cold. Most likely will be around the same $ to run as your smaller one from starting that compressor up from a dead stop every time. You need to try and get the initial heat load down first witch is coming from your lights. I would start by separating your cool tube exhaust and think about insulating your room before buying larger more expensive equipment. You could also install a electronic tempature controller inline with your AC power to control set points and the deferential.

Move the fan to the exhaust end of the ducting. The closer to the outlet, the better. Fans work best pulling, not pushing.

Duct your lights in series, not parallel. Use rigid ducting wherever possible, and keep the circuit as short as practical. I also like to insulate my light circuit ducting, hoods, and AC exhaust. Also, using a cheap glass air filter will help keep your bulbs/reflectors dust-free. For the most part.

Don't worry about 80+F degree air to cool your lights. I've used 120+F air. The important thing is that you have airflow over the bulb.

A 2 hose portable AC is 10x better than a single hose.

Hey guys, thanks for all the responses. So, here is what I've decided to do, I hope it will solve my problem:

Right now, I am running a 5000BTU single hose air conditioner. I am going to buy a 14,000 dual hose portable A/C, but I am going to place the unit outside the grow room, directly in front of the window. I am replacing the cool tubes with two hoods, that I am going to connect in-line, and I am going to use insulated ducting. Currently, I have a six-inch hole in the door through which the ducting for my 5000BTU is inserted. Once I remove that AC unit, I am going to drill that hole to 8-inches and cover it with a dust filter for a passive intake. I figure these modifications will solve my problem.

Oh, and I've returned the LED fixture. I too was thinking that I would be disappointed with it.

phreeezer said:

Hi guys,

Long time lurker here, first time poster. I've had a grow room in a walk-in closet I have for around 3 years now, and have had reasonable success. I desperately want to improve my grow environment, but I'm having a frustrating time keeping my grow room cool.

I have two 600W HPS lamps in cool tubes in a walk-in closet that measures 6' X 5' X 8'. Air is drawn through a carbon filter that sits near the ceiling in a corner of the grow room with a 6" duct fan (334CFM), through a Y splitter, through the 2 cool tubes, through another splitter (to join the two ducts back together), and out the closet door into my bed room. I have a 5000BTU portable air conditioner that sits in the corner of the grow room as well. With this setup, my grow room regularly averages temperatures ranging from 80F to 85F.

I am getting ready to upgrade my grow room, and I would really like to modify my setup to keep temperatures down. I've attached diagrams of my current setup, and my proposed setup. I was thinking that I could put ducting through the wall of the grow room, into the next bedroom, and connect it to the window to draw outside air in to cool the lights, and then spit it back outside again. But, because I live in the south, the air temperature outdoors is usually in the eighties. So I'm not sure if this would even solve anything.

I've attached diagrams of my current setup, and my proposed setup. I'd appreciate any advice you guys could give me... I've been driving myself nuts over this. I'm considering switching to LED because of this issue, but the one I would want to replace my current 1200W would run me $1700. I'm not crazy about that idea. Really, all I want to do is get my temps down... and I feel like there has to be a way to do that without buying LEDs.

One more thing--I've ordered a water chiller for my system, and I plan to put it outside the grow room.View attachment 3465567 View attachment 3465568

Click to expand...

Are the ducts insulated? These will dissipate heat so using silenced insulation during will help.

I also think that having it all in line would be more efficient. You have lot of ducting and hence a lot of surface area to loose heat into the room. In line is also more efficient in terms of air movement.

You need to move the air faster. Using your proposed set up...dont pull the air from outside. Just pull from the next room. Use two 6 inch duct lines, one to each hood. After the air is pulled seperately through each hood Y them together with a duct that has one 8" opening and pull with an 8" fan at about 700+ cfm. That will help. And may save you from beefing up your ac.