For SoCal weather is my 720 CFM fan enough or will I need an AC?

As the title of the thread says, I'm a Prop 215 patient located in Southern California and the heat problems in my room are just killing me. I thought that my ventilation was set up properly but I'm thinking it's not? I used to think that growers in areas like mine always required the use of an AC because when it gets 90-100 ventilation can't keep up, but lately I've been reading that this is apparently not true and if you need an AC your ventilation isn't right? Please look at my set up and let me know what I'm doing wrong, I desperately need to fix this..



I'm currently running a single 720 cfm fan to move the hot air from my air cooled lights out of the grow room, but it's going into the room the grow room is in. The first 4 photos show the exhaust for the lights, there is currently no exhaust for the box because my room was hotter when that was installed. I've since closed the exhaust to the box off and turned my AC back on and my temps are a bit lower, but I know I'm still not doing something right. You can see in the 5th photo that the exhaust for the lights is just venting into the room my grow room is in, I rent the place so I can't really make any holes in the walls but I'm getting about ready to say screw it and vent the heat from the lights outside. The 6th and 7th pictures are of my intakes, I have two 4 inch intake holes with one of the holes being connected to the booster fan you see in picture 6. Do I need more intake holes or do they need to be larger? Is the booster fan actually restricting the amount of air that can move through my ducting? The last photo is just my other inline fan venting air from the main room out of the window, should I have this hooked up elsewhere?

Basically what I need to know is the following.

1) Is my ventilation properly set up? If not, what do I need to do to make it set up to properly drop the temps?
2) I've heard many people say that AC isn't necessary with proper ventilation, is proper ventilation still good enough when it's 90-100 outside? Is there a way to set up your ventilation to combat such high temps or will an AC be needed?
3) Any other input you may have.

Any help would be greatly appreciated as I really need to get this figured out. I'm looking at getting myself a nice $200 10k BTU air conditioner because I'm thinking that's what I'll have to do, but before I do that I want to give ventilation one last try. I've been reading so much about it and I still can't seem to figure my problem out, I really really hope someone on here can help me..

Youll need AC. You dont have to use air cooled hoods,but if you do you should definitely vent them out of the room. Blowing hot air through a hot hood back into a hot room isnt gonna bring your temps down sufficiently when its warm.

To not use AC you gotta have cool temps to offset the heat if youre using it to cool hoods and exchange room air. If the outside temps are above what you want your room temps to be, theres no special way to do your ventilation that will make it work.

BustinScales510 said:

Youll need AC. You dont have to use air cooled hoods,but if you do you should definitely vent them out of the room. Blowing hot air through a hot hood back into a hot room isnt gonna bring your temps down sufficiently when its warm.

To not use AC you gotta have cool temps to offset the heat if youre using it to cool hoods and exchange room air. If the outside temps are above what you want your room temps to be, theres no special way to do your ventilation that will make it work.

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I see, so all the people claiming they only need a ventilation set up most likely have the suitable climate for it where it's not 90-100 all week long. Now that I've determined I'll need an AC (I'm thinking 9k-12k BTU?) I'll just need to decide what is the most efficient to cool.

The entire room that my grow room is in measures out to 12x10x7 and my actual grow room is 10x6x7. I've been thinking this whole time that I need to cool the grow room itself, but what if I cooled the space that isn't taken up by my grow room? Wouldn't it be easier on the AC to cool the space not taken up by my room which is about 2ftx10ft since it's smaller? Even though the heat from the lights vents into this room, it's still a much smaller space to cool, especially for a 10k BTU AC.

Would I be better off just putting the AC into the grow room itself and cooling the entire box? Or should I use the new AC into the window of the main room the grow room is located in with the hopes of lowering the ambient temps of the room. I figure if I lower the temps of the main room then the cool air will be sucked in via the intakes right?

I am in Cali too.....and this weather we are having right now has my temps up as well!!! 95 degrees yesterday and today....Good thing about where we live is our temps are fairly mild unless your in the valley or something. As summer hits we are going to get that 80-90 degrees for a couple months. Always random heat waves, I either pump my AC which gets expensive or plan my grows around the heat. I have an outside patio upstairs which is nice for a summer grow for a couple months and turn off my lights to save on electricity. Think about it your grow room temps will always be hotter than the ambient temp in the surrounding area. Right now my AC is set at 76 for my house so upstairs in my closet where my grow is I am sitting around 80. I have a small setup with (1) 400 HPS in a much smaller area. I would put the AC in the grow room unless you can rig something up that is pulling that cool air directly into that room. How big of lights you running?

I'm running 2 1000 watters at the moment. It's looking like I'm gonna put it into the grow room but my other idea was to put it in the window of the main room the grow room is in. This way I could pull the now cool air from the main room into the grow room, but now that I'm thinking about it I don't believe it's practical. The other thing is that I have a tiny 5k BTU window ac in there as of now and it's trying to cool a 10x6x7 room and I bet that's the source of my high electric bill right there is how hard I'm making that thing work. I'm thinking that if I get a 10-15k BTU window unit then it'll be able to cool the room with ease compared to my 5k BTU unit struggling. So although the new AC unit I want is 3 times as powerful as the one I currently have, I think I'll actually save electricity since the 15k will be more efficient than the 5k for the size of my room correct?

I believe you would be correct....I am not AC expert but my mom had a similar situation in her house she had a little wall mounted AC unit in her condo. In the summer she ran it 24/7 and it her electric bill was high. When the thing died she got a new bigger more efficient unit which was not on as much. Seemed to help a little. Maybe running lights at night instead? Two 1ks will put off some heat so yah got to get cooler air in to run through your lights and exhaust hot air out of room. I am lucky I own my place it has an attic and I can vent hot air there. I want to bump up to 600 and add bigger inline fan....heat is always fun to try and controll :/ How hot you getting with this weahter?

Yeah you definitely wanna run lights at night, I do mine 7 - 7. What you mentioned about climate was correct. Im lucky enough to not have to use AC and I run a bunch of lights, but I live in Oakland near the water. The night temps are 40s in the winter and 50s in the summer.

There is a guy in LA who does videos on youtube named 'growingforfreedom". He has several 4000 watt rooms with AC and talks about his setup in detail pretty frequently, he does Q&A stuff too.

As a general rule 4k btu per 1k light.to really make an impact bring the air from outside your grow room over your light and then outside.so that air never comes in contact with your ac air.then your not working your ac so much.hope that helps.also get rid of any extra bends in your pipes/hoses so your fan works as efficiently as possible.every bend or turn drastically effects your fans strength.

bfb1999 said:

As a general rule 4k btu per 1k light.to really make an impact bring the air from outside your grow room over your light and then outside.so that air never comes in contact with your ac air.then your not working your ac so much.hope that helps.also get rid of any extra bends in your pipes/hoses so your fan works as efficiently as possible.every bend or turn drastically effects your fans strength.

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Yeah I know about not having bends and that's actually why I have the hole on the right light exposed, do you think it'd be better if I connected the tubing back to one of my intake holes though? If I do that then my exhaust fan won't be exhausting air out of my room via the lights. What do you think? As for the 4k per light, that's good to know because I was thinking I'd need around 12k BTUs but it's looking like 10k will be enough?

rwbrock said:

I believe you would be correct....I am not AC expert but my mom had a similar situation in her house she had a little wall mounted AC unit in her condo. In the summer she ran it 24/7 and it her electric bill was high. When the thing died she got a new bigger more efficient unit which was not on as much. Seemed to help a little. Maybe running lights at night instead? Two 1ks will put off some heat so yah got to get cooler air in to run through your lights and exhaust hot air out of room. I am lucky I own my place it has an attic and I can vent hot air there. I want to bump up to 600 and add bigger inline fan....heat is always fun to try and controll :/ How hot you getting with this weahter?

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Does it matter how hot the air going through your hoods is though? If the point of an exhaust is to suck the hot air out before it can produce heat then wouldn't putting cold air through the hoods be a waste of cool air? I ask because I have a nice 8 inch hole that used to be an AC vent and it brings air from underneath the house which can be cool even on the hottest days. If venting the cool air through the hoods really makes that much of a difference then perhaps I should hook it back up to that AC vent in the ground? The problem is that I have that vent being used as a passive intake hole so that the cool air from under the house can come into my box and hopefully make things easier on my AC. Plus if I'm running an AC, won't some cool air from the box be sucked right through the lights because of my inline fan?

But man, the weather gets ridiculous where I'm at. I'm in a more deserty climate, about an hour away from Palm Springs. The past few days we've been dealing with 90-100 degree weather which has been horrible for my box. And not only that, it's hot even when you sleep. I do in fact have my lights come on at 7:30pm until 7:30 am, both for cooler air and not to use during peak hours. I used to do 1:30-1:30 and I've noticed a bit of improvement since I changed but I'm still having trouble because it just gets hot out here. It's looking like I have a week of 80-85 degree weather, but I still need to get an AC asap so I can run things more efficiently.

BustinScales510 said:

Yeah you definitely wanna run lights at night, I do mine 7 - 7. What you mentioned about climate was correct. Im lucky enough to not have to use AC and I run a bunch of lights, but I live in Oakland near the water. The night temps are 40s in the winter and 50s in the summer.

There is a guy in LA who does videos on youtube named 'growingforfreedom". He has several 4000 watt rooms with AC and talks about his setup in detail pretty frequently, he does Q&A stuff too.

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You get to the 50s at night during the summer? Man how I envy you! It's been so hot out here that when it's 90-100 out I wake up at 3am because I'm sweating like mad, our nights don't get that much cooler than our days sadly. But yeah, I do 7:30-7:30 and it still gets pretty hot but not as hot as 1-1 lol. Looks like I'm gonna need to run an AC but at least it's gonna be cheaper than the one I'm using now most likely, it sounds like I'm literally burning money. I've been scouring craigslist for hours constantly looking, I'm hoping I'll find something soon! And thanks for the youtube recommendation, I've been looking for something just like that. It's easy to find grow journals on the internet, what's not easy is finding journals that share the exact same situation with you. I think I'll learn a lot from those, thanks again.

How much are you looking to spend on the AC unit? Something like this would work but not sure about your budget?

http://orangecounty.craigslist.org/for/3804903199.html

rwbrock said:

How much are you looking to spend on the AC unit? Something like this would work but not sure about your budget?

http://orangecounty.craigslist.org/for/3804903199.html

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Is that a portable? I've been reading that portables are actually worse than wall units for grow rooms, is that true? I'm looking at 100-200 to purchase a used AC and it's gonna have between 9-12k BTUs for sure, I want it to be so powerful that I can run it every 15-30 minutes and still be fine.

Portables blow man. They all suck some inside air even if they are dual hose. Exhausting dank air to the world.
Get a window unit. I would go w/ the 12k personally.

Better to have a little more and not need it than to need it and not have it.