Extreme heat issues... help

So I just got a 400w HPS and 36x20x68 mylar grow tent... As soon as I set everything up and turned the light on temps quickly skyrocketed to 100+ degrees F. This is even with an intake and exhaust fan running. There's no cooling unit for the light itself... I don't really know what to do. Even with the tent open its extremely hot. Help?? It's not like I can put an air conditioner in my closet. I pulled the plug on everything. Under CFL's I was at an average temp of 75--- this is CRAZY. I had no idea it would be THAT hot... with fans running and everything. What am I supposed to do? My plants are in the dark right now until I can figure this out... maybe just put them back under the CFL's for now if I can figure out a way to hang them in the tent. Any ideas on how to control heat?

Air cooled hood is going to be the only solution.

awesome... so i need a totally different light... mine just has a ballast. maybe i can build something...

I've got the same exact size tent. I do live in a trailer in Florida at the moment which does get hot, especially in the summer.

Anyway, the past August I finally started my first grow. In my tent I had a 250W HPS and 4 - 4 foot T5 HO Flourescents for side lighting. My temps also were out of control, I'm talking like 120 deg F with fans and everything.

In my living room, instead of a window air conditioner, I've got one of those floor models with an exhaust tube that vents out the window. This is insane but I moved my tent into my living room, unzipped and completely opened the front of the tent, took a large piece of panda film and draped it over the tent and air conditioner in effect extending the tent to enclose the air conditioner and even then I was getting temps around 85+ during the day inside the tent but I was able to grow something. I guess all the ventilation and the cold air from the A/C blowing right on the plants kept them at a good temp.

So what I've done is removed the HPS and kept the T5's and have spent a fortune on LED's to replace the HPS. At the moment it's cold outside so I actually have a small heater in front of the tent to keep the temps up. So theoretically I've solved the heat problem for this summer. I'm on my second grow which is the first with LED's so being basically a noob with LED's it remains to be seen what I'll end up with, but so far the veg part is going so well it's almost out of control.

So after saying all that, good luck but that's what I've done. I knew an HPS put out a lot of heat, but damn, like you've experienced, I never dreamed it would be that much heat. Maybe it's the small tent that's the problem, and if it were like a 4' x 4' x 6' foot or something it wouldn't be so bad, but in my case, it's really all I've got room for.

SmokeMore said:

I've got the same exact size tent. I do live in a trailer in Florida at the moment which does get hot, especially in the summer.

Anyway, the past August I finally started my first grow. In my tent I had a 250W HPS and 4 - 4 foot T5 HO Flourescents for side lighting. My temps also were out of control, I'm talking like 120 deg F with fans and everything.

In my living room, instead of a window air conditioner, I've got one of those floor models with an exhaust tube that vents out the window. This is insane but I moved my tent into my living room, unzipped and completely opened the front of the tent, took a large piece of panda film and draped it over the tent and air conditioner in effect extending the tent to enclose the air conditioner and even then I was getting temps around 85+ during the day inside the tent but I was able to grow something. I guess all the ventilation and the cold air from the A/C blowing right on the plants kept them at a good temp.

So what I've done is removed the HPS and kept the T5's and have spent a fortune on LED's to replace the HPS. At the moment it's cold outside so I actually have a small heater in front of the tent to keep the temps up. So theoretically I've solved the heat problem for this summer. I'm on my second grow which is the first with LED's so being basically a noob with LED's it remains to be seen what I'll end up with, but so far the veg part is going so well it's almost out of control.

So after saying all that, good luck but that's what I've done. I knew an HPS put out a lot of heat, but damn, like you've experienced, I never dreamed it would be that much heat. Maybe it's the small tent that's the problem, and if it were like a 4' x 4' x 6' foot or something it wouldn't be so bad, but in my case, it's really all I've got room for.

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yea sounds like we've got alot in common... right now its kinda chilly down here in fl and i don't have any kind of room really... i could put it in front of a freestanding a/c unit but my whole idea was to keep this all hidden in the closet. i guess i have no choice- the air the fans are bringing in to "cool" is already like 70 degrees.

bRandom said:

yea sounds like we've got alot in common... right now its kinda chilly down here in fl and i don't have any kind of room really... i could put it in front of a freestanding a/c unit but my whole idea was to keep this all hidden in the closet. i guess i have no choice- the air the fans are bringing in to "cool" is already like 70 degrees.

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Yep, sounds like we do have a lot in common.

And I know what you mean about keeping everything hidden. Friends are wanting to come over and I'm like, uh, well, uh, um, you see, uh, it's kind of messy in there and I really don't want anybody over right now.

And I just realized the other day that when I open the tent to water or give them nutes, the incredibly bright pink light from the LED's shines on the closed curtains in the window. I'm sure the neighbors don't suspect anything, but if anybody were to happen to be looking right at my place at the right moment and see my silhouette in that pink light they'd be like "WTF is that?"

Now I know so I'm careful, and there is risk in growing, but as I'm sure you also realize, I think it overall is a whole lot safer. From seed to smoke and nothing ever leaves my home is safer than driving to a dealer, paying for whatever is randomly available, driving home with it, wondering if you're being watched or followed or gonna get stopped, etc., etc.

hey smokemore, where is your hot air exhausted to?

SmokeMore said:

Yep, sounds like we do have a lot in common.

And I know what you mean about keeping everything hidden. Friends are wanting to come over and I'm like, uh, well, uh, um, you see, uh, it's kind of messy in there and I really don't want anybody over right now.

And I just realized the other day that when I open the tent to water or give them nutes, the incredibly bright pink light from the LED's shines on the closed curtains in the window. I'm sure the neighbors don't suspect anything, but if anybody were to happen to be looking right at my place at the right moment and see my silhouette in that pink light they'd be like "WTF is that?"

Now I know so I'm careful, and there is risk in growing, but as I'm sure you also realize, I think it overall is a whole lot safer. From seed to smoke and nothing ever leaves my home is safer than driving to a dealer, paying for whatever is randomly available, driving home with it, wondering if you're being watched or followed or gonna get stopped, etc., etc.

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It's totally worth it to deal with these little issues when they come up... cause eventually I'll have everything worked out and smoking my own. Can't beat that. People don't jump to the conclusion that you must be doing something "illegal" when they see a weird light in your house either. So we might feel paranoid sometimes but you're right cops aren't coming to the average person's house asking questions so there's not as big a risk as handling business in the street.

air cooled hood with 4" ducting running from hood to stanley blower then out the box. the cheapest solution for a 400hps. get your air cooled hood from plantlightinghydroponics and search google shopping for stanley blower..... search diy stanley blower mod for more instructions!

I do not believe even an air cooled hood will do the trick with temps that high. I had do do as was suggested above and get a floor a/c. Expensive as a motherfluffer, but worth it if it is your only option.

del66666 said:

hey smokemore, where is your hot air exhausted to?

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Hey del66666,

I have a 4 inch carbon filter in the tent connected to a 4 inch inline fan which is connected to 4 inch ducting which goes to a back bedroom. I'd like to vent it outside but in order to do that I'd have to cut a hole somewhere. I could vent it out a window but there are homes all around me and all my windows are "visible" so I would have a visible tube blowing out air all the time. This may not be an issue, but I'd rather play it safe.

Now I do have the exhaust vent for the a/c sticking out of one window, which beleive it or not, a couple of neighbors have already asked me about. I just tell them the truth "oh, instead of a window a/c I have a floor unit and that's the exhaust for it". I guess I could use the same excuse for an exhaust duct from my fan, but I don't know, I guess I'm too honest and me saying the exhaust from the a/c is the truth and if I had to fib on the other I'd be scared they'd suspect something. Maybe it's just me.

Now theoretically, with things like I had them, with the a/c basically enclosed in the tent, the a/c exhaust would be a recipe for disaster, that air should absolutely smell so strong it would be a dead giveaway. I solved that problem by doing the following.

I had the 4 inch carbon filter in the top of the tent which pulled out any hot air that would rise to the top, and filter it at the same time. I had the a/c ducts pointed slightly up. Right at the base of the a/c, and also basically inside the tent, I had a 6 inch fan and carbon filter blowing air basically out the bottom of the tent into the room. This created what I think was a circular motion to the air in the tent and also provided filtered, odor free air back in the vicinity of the a/c which allowed for odor free air to be pulled into the a/c intake at the back of the unit, which is the air that gets acted on by the a/c compressor, which is the hot air that blows out the a/c exhaust, which is now odor free.

If I didn't use that 6 inch filter and fan, I think the a/c would have been pumping enough air to overwhelm the 4 inch filter and fan, and therefore, it would have smelled inside the room, thus allowing for smelly air to be taken in by the a/c, thus blowing hot smelly air outside.

I now all that sounds like an incredible expense and hassle, but my living in a trailer (i.e. oven in the summer) is the main problem, and I was gonna grow and have something to smoke no matter what! Now that I've switched to LED's and just have the T5's making most of the heat, I think this summer will be manageable, I should be able to keep the tent closed, have the a/c running as normal, and just use the 4 inch filter and fan exhausting air out of the tent. If for some reason that doesn't work all the way, I can always plug in the 6 inch fan and filter just to be safe.

Sorry for the long reply.

I personally don't think you have provided enough info on this. Another member posted on it. Retrace your steps in your configuration of your venting system before taking further action. What is the source of your intake? I think you said it's a closet grow? You sucking air from the room to cool your closet? Where are you dumping the air? What kind of exhaust fan are you using? What is its rating?

im guessing you live somewhere hot ? cause i just vent mine into my room and crack a window, ambient temp is about 70 rising to 75-80 when lights are on........

Yea it's not been that hot down here lately but all my "security" in the closet has made it pretty air tight. Vents out the top of the tent and intake is near the floor, recycling the air in the closet except for when I open the door, which is often. I was thinking about going up to the attic crawlspace and venting straight out through the ceiling but this seems like an extreme measure to take. Thought I might even be able to link my intake tube to the main A/C unit for the house. When I have the tent open with one fan blowing "cool" air in and one fan exhausting right near the light bulb temp is like 79-81. Which is alot better than when I started fooling around with the fans. Anyway I have three more fans coming soon so I think that with two intake and two exhaust I might be able to close the tent up and still keep temps under control. If I have to I'll buy a air cooler that uses water and just stick that near my intake. Thanks all for the suggestions.

Did you say you have 2 fans? Try using them both as exhaust, and just having a passive intake. This will exchange the air faster. You don't have the ballast inside the tent do you?

I did this recently ( using a 6 inch, and a 4 inch fan in a larger room ) i have a 1000w hps, and i store the ballast in the room, this keeps the temps down quite well

also, buying an air cooled hood would have been a lot cheaper than buying 2 more fans

Also, keep an eye on where your exhaust air is going....my room is in a small hallway, and i had to add an extra hose to the passive intake to bring in cool air from the next room. Otherwise the air in the hallway was slowly heating up with the exhaust, and simply recycling that hot air into the room.
Proper ventilation and heat management can become sort of an art, find what works. I really dont think having 4 fans on such a small tent is necessary, your noise will be out of control lol

No the ballast isn't in the tent. I got a good deal on some fans so it's not a big expense. About recycling hot air, I'm there... in fact when I open the tent it heats up my whole room (outside the closet) which is pretty big, about a 20x30 foot space. So during the day (when no one else is home) I open the door to my room also to bring in more cool air from the rest of the house... and it just looks like the fucking sun is rising in my bedroom. I think I've just got to get an air cooler in the closet itself.