Heat-What I am doing wrong?

[sirsmokealot23]

Well I started to get heat problems with temps around 90 so I decided to add a 500 cfm exhaust fan at the top of my room to take out the heat. The problem is that it only made the temps go down like 2 degrees. Is this because I have no intake air or is my fan not big enough? My room is less than 800 sq ft. I have a 1000w light with a 180 cfm exhasut fan connected to it and the duct is very hot so I know its working. Instead of hooking up the new 500 cfm fan at the top of my room should I switch it out with the 180 cfm connected to the light? Will any of this help out my temps get at least down to the low 80's? Sorry I got so many questions...I'm just not sure to do with the items I have. Thanks for your time. Also I got some 5-10 in. plants and was wondering how far to put them away from the 1000w mh light? I got them 3 and a half feet away currently.

[Dreadscale]

welcome sirsmokealot23

Is your 1000w enclosed ,with an intake ported from outside of the room, and the exaust also outside?
Do you have passive air intake lower in the room than your exaust , that should be removing heated air at the top?

If you got a photo or a sketch of your set up that would help a bit for more accurate answers.

Good Luck

[McDanger]

Less than 800sf, that is like 20X40, or do you mean 80sf. you need at least passive intake down low, then if you put your bigger fan on the light ducted out of the room you should be able to get it down. What is the ambient temp outside the room?

[TheMetal1]

I can tell you this for sure... you need some sort of intake to circulate fresh air. Plain and simple... should drop your temps considerably.

Have you ever tried to suck through a clogged bowl? Imagine that the passive intake hole is acting as your poking tool. Clear up that air path so your babies can breeeeeeathe. :stoned:

[McDanger]

Great example, just like taking your thumb off the carb.:D:D

[stinkyattic]

IF your light is air-coolable, I would swap out your fans so that big one is on the light. Also consider insulating the duct from the light to the fan.
Remove all obstructions from the passive intake and make it twice as big as the total exhaust hole size, including the exhaust from your light.
Make sure the exhaust from the light is not going into the space that the intake is pulling from. Send it into a different room.
A/C the room where your intake is coming from.

[sirsmokealot23]

first off thanks for the response Dreadscale. I have an exhaust from the air cooled reflecter but I don't have intake into it. Will that make a big different if I put that on? The only other problem is that I am out of holes to get some outside air. What if I set up an intake into my hood and then that would lead to the outside through the exhaust. Also just to add I dont currently pull air from anywhere but I do have a 3 by 3 hole into my space. I'm doing this grow in an attic so the spot leading up is always open. Thanks again for your help.

[sirsmokealot23]

Sorry I meant 800 cu ft. I have a 10 x 10 room that is 8 ft high. Like I mentioned to Dreadscale this grow is in a attic and the temps outside are in the high 80's and low 90's. Inside my house the temps are in the low high 70's low 80's. I'll switch my fan today and see what happens. Thanks for the help.

[sirsmokealot23]

Hey TheMetal1. Thanks for responding. I do have a 3 x 3 port open. Do you think this is good enough or do I actually have to pull the air in? I totally understand the clogged bowl example. Thanks. Also the air is my house is only high 70's and low 80's will this air be cool enough to even out with the heat if I do pull it in. Just wondering because I read on a forum a bit ago that if you aren't sucking a/c air in then there is no point because the difference is little if any. Thanks.

[sirsmokealot23]

Stinkyattic- today I will switch out my fans and add some insulation around the duct. Thanks for the tips! I had a hard time understand what "Remove all obstructions from the passive intake and make it twice as big as the total exhaust hole size, including the exhaust from your light." Maybe I am just stupid but it just didn't click to me. All of my exhaust goes to the outside of my house and all my intake comes through the entry space into the attic (grow room) from the house. Should I be pulling and sending it to some place else? I wouldn't do it like this if I had a spare room to grow in but I'm stick in an attic. Thanks again for your help and time.

[TheMetal1]

I'd refer to StinkyAttic's post regarding the size of your intake. As far as pulling air in? If you have a sealed enclosure (grow tent, box, cabinet, etc.) and you mount an exhaust... you will not need a fan to "pull" air IN. People do use them (referred to as Active Intake) depending on their situation... but you should be ok starting out. Since the space is sealed, the only way your exhaust can pull air OUT is by giving it an open source (i.e. a big hole in the side :jointsmile:)

I'm kinda confusing myself now. Either way, back to the bowl analogy :hippy:

The clogged bowl = Your sealed grow space
Finger over carb = No passive intake in grow space
Your lungs = Exhaust fan pulling air through

You try to inhale... but your finger is blocking it. You move your finger slightly... a little air comes through, but not enough. You completely remove your finger... total airflow :thumbsup:

Now, would you need a small fan where the carb is to push the smoke/air into your lungs?
- Probably not... but with larger spaces, where negative pressure is more difficult to maintain, it can help.
Woah... I'm losing myself now.
As far as the a/c air?? Well, I don't even have a/c in my place... and my box temps are about 79 during the day and maybe 60 at night? Not sure about that night temp because I just flipped to 12/12. Haven't had too many "nights" to build an average from.

But yeah, check out Stinky's stickies... and the grow room set-up sticky by Rhizome. Lots of reading, but it's sooo worth it!! :stoned:

[Dreadscale]

Hey sirsmokealot23 :thumbsup:

I'm sure by the screen name you thought I was an Iksar ShadowKnight, but IRL I am a Carpenter.:D
If your grow is in an attic, your temps. are way higher than outside.
If your space has no insulation you need to install at least some R-19, cealing,walls, and floor.
2 reasons, heat loss/gain, and heat signature. In winter you will lose all your heat/summer gain, and also have a big signature." Only spot on roof with no snow"
In a pinch you can pull air from the floor below the grow. Find an uninsulated wall " Most Interior Walls" and drill a 3" hole or a 4" on a 6" wall, in the top plate. Find the bay below,"Between the Studs", and cut in a vent. A lot of sizes and styles are available for the vent cover. With an exaust this will work great. "BUT not in an OPEN attic"
In a 10x10x8 attic you must live in a Victorian or a real high end home.

Just pull in some fresh air, AC is good, but fresh is a need.
Good Luck

[stinkyattic]

Try to pull your intake air from the living space, which I assume is a comfortable temp.
Exhaust to outside is good; don't forget your carbon filter!
Insulating the attic is also important. I live in a Victorian with a walk-up attic that is insulated really poorly, with a big window that catches afternoon sun... it's blisteringly hot up there some days, and I fought high temps every time I tried to stink up my attic ;) Do you have a way to reduce heat entering the attic, such as putting up blinds on any window you might have, and keeping the attic door closed in summer so heat from the house can't get up there? Then you'd need to think of how to get your cool intake air to the tent.
You're getting plenty of solid advice here! Good luck!

[sirsmokealot23]

I didn't even think about the heat from the house floating up into the attic. I think I'll take your advise and put in an intake fan. I can put the board back in and then cut a hole in it for ducting. That way I'm not getting hot air floating in..I'll be getting cool air pulled in. I've already got the whole attic insulated because I too live in a victorian. O one more question if you have time. I didn't want to start a separate thread for this but... Say I have a 150 cfm exhaust fan and then I connect a 200 cfm exhaust fan with ducting to that one. Will the fans work at 350 cfm or not? The reason is because I have a lot of fans but not many outlets for exhaust. Thanks again for all your help along with everyone else that has added to this great site.

[stinkyattic]

Actually you are going to end up DECREASING your cfm efficiency and here's why:
Adding another fan, especially a mismatched one, is going to add TURBULENCE to your duct system and acutally BLOCK air flow. Clear, straight, smooth ducting is best, with just a SINGLE fan. By the same token, if you have an active exhaust AND an active intake, the fan cfm must be perfectly matched, or you're actually better off just running an exhaust fan to PULL air through the whole system, leaving anice big unobstructed intake hole- preferably in a cool area. If you can bring cool air up from the basement via an unused chimney, or from and iar conditioned room via a duct, that would be nice.