Seeking advice on my new space

[420fied]

Hello folks,

I have grown for years on a small scale. My garden has been ran on (2) 600 watt HPS units in an 8'x'8'x8' flower room with a 5,000 BTU window AC. This space was out in the sticks so there was no need to worry about odor control, ventilation, etc. Now I am changing spaces and in order to avoid being given an inmate# I need to make sure this is done right the first time. Obviously, I want to keep my garden odor free and cool. The problem is, this is the first time I've done a build of this scale so I have a few question for those who have done this before and can offer sound advice. I will try and be as detailed as I can so that you can get an idea of what I'm working with.

This house was built in the early 1900's and has no central air conditioning. Originally it looks as if there was a huge attic and someone decided to turn it into a second floor.

When I started the cleanup I noticed that there was no insulation so the first thing I did was insulate the 5' side walls with R30 and blow insulation into the sides and on top. The angled part of the ceiling of the room is roughly 6" away from the roof sheeting so I'm basically working in an attic.

I have provided drawings of what the space looks like now, before we do any framing, etc.

When looking at the 2nd drawing, you're getting the view as if you're looking through the space from front to back. Imagine you're standing where the main entry is and you're looking to your right, into the flower room.

Now... here are my thoughts/questions

Fan/Filter combos: I'm looking for a quiet and effective unit. Here's the rough math: The flowering space is 20'x11'x8' which gives us 1760cu ft. I divided by 5 which tells me that I'd need a fan that exhausts with a minimum of 352cfm in order to treat the space in 5 minutes.

1760/5 = 352

I've saw some 6" and 8" units which are in the 450-590cfm range. However, everything I've read leads me to believe that I will need a larger fan to treat this space effectively.

Notice that the room has an angled ceiling so the space is not truly 1760cu ft, it's probably more like 1550cu ft.

1550/5 = 310

Anyway, from what I've read I believe that I will need to set up a passive intake which I plan to draw from the crawl space. I know that my intake needs to have some correlation in size with the size of my exhaust fan. Much that I have read leads me to believe that I'll need a fan larger than 6" to treat this space. If I have to use an 8" or larger fan I'm wondering what I can do for a passive intake. I plan to pull the air in the room through the carbon filter and exhaust it out the top of the roof. As you can see, there are windows on each end of the entire space. I will either be studding in walls or using heavy, white, roll up plastic and 1x to build walls which will seal the flower chamber and the veg chamber.

My hoods are the open Quadray reflectors and are not air cooled. (4) 600 watt units will throw some heat so window ACs will be needed to cool the flower chamber but it will exhaust odorous air out the back. If I'm running the exhaust fan/filter combo will that kill the smell before the window AC pumps it out into the neighborhood? Or... would it be a good idea to totally seal the windows and room off and try and cool the space another way?(portable/no exhaust AC'S?) Does something like that even exist?

Other questions


*What size fan/filter combo will I need to keep this flowering chamber odor free?
*What fan/filter combo is the best and quietest?
*What are my best options for introducing the passive intake? Can I use more than one in various places? (For example: It's determined that I need a 12" fan. Can I place (2) separate 6" passive intakes in the space?) How large will the intake need to be based off of the fan needed to scrub the room?
*What is my best avenue for cooling this flower chamber?


Also, I've read about scrubbing your room vs. exhausting your room. Can someone elaborate on that for me as I'm fairly clueless when it comes to odor control/ventilation? Would it be smarter for me to try and totally seal off the flower chamber and then scrub the room without venting it out the top while depending on the Window AC's to keep it cool?

I know that I probably didn't provide all of the necessary info needed in order for you to answer all of my questions so I will monitor this thread and provide any additional information that you require. Obviously, this is a huge step so I want to make sure I do this right. I truly appreciate any advice/information/personal experience that you can give me.

 

[420fied]

I want to help you to get out from this problem but i was not able to configure out your problem properly. May be someone else can do this. Best of luck.

Thank you. It's the thought that counts.

 

[IndoorHaze]

For walls, instead of plastic or studs, use 3/4" foamular sheets. Search Home Depot for details. 4x8s are around $15, can be cut with boxcutters, and glued with Gorilla glue or epoxy.

You're lights are going to put out about 4100 BTUs of heat, so you'll need at least that in A/C capacity. I would use the A/C to cool a room or some empty space upstream of the garden airflow and draw my garden air from there. This way, you won't risk any smell being leaked through the A/C units. I would place my carbon filter/exhaust fans up near the ceiling of the garden and vent out wherever it's convenient. With a room that large, I think 5 minute air changes are overkill. You have plenty of volume that your plants are not going to suffer from using up the 02 or C02 too quickly.

My two cents, hope to see whatever you decide to do with the space.

 

[420fied]

For walls, instead of plastic or studs, use 3/4" foamular sheets. Search Home Depot for details. 4x8s are around $15, can be cut with boxcutters, and glued with Gorilla glue or epoxy.

You're lights are going to put out about 4100 BTUs of heat, so you'll need at least that in A/C capacity. I would use the A/C to cool a room or some empty space upstream of the garden airflow and draw my garden air from there. This way, you won't risk any smell being leaked through the A/C units. I would place my carbon filter/exhaust fans up near the ceiling of the garden and vent out wherever it's convenient. With a room that large, I think 5 minute air changes are overkill. You have plenty of volume that your plants are not going to suffer from using up the 02 or C02 too quickly.

My two cents, hope to see whatever you decide to do with the space.

Excellent idea for the walls. I will look into that for sure. The only other room up there is the veg room which will produce very little odor. As you can see it also has a window AC There will be 4-6 short moms in there under t5s. I'd have to draw air from that room into the flower room.

 

[IndoorHaze]

Excellent idea for the walls. I will look into that for sure. The only other room up there is the veg room which will produce very little odor. As you can see it also has a window AC There will be 4-6 short moms in there under t5s. I'd have to draw air from that room into the flower room.

Window A/C units vary wildly in how much indoor air makes it outside. Maybe you can move it out of the flower area and seal up the window. Or, if you're the handy type, you could open the case and do a seal job on it between the evap and condenser sides. Other than that, maybe invest in a portable split A/C unit. Just noticed you're going up to four 600 watt lights, that would put BTUs at around 8200. Don't know how committed you are to the Quadrays, but sealed hoods would probably pay for themselves in a summer or two. If not, the power company would love it if you put heaters and A/C in the same room and let 'em fight it out. Hmm, you might consider doing a drop ceiling with cutouts for the lights. Pull your exhaust from above that and maybe keep the heat moving away from the grow space. Looking forward to seeing what you come up with.

 

[420fied]

Window A/C units vary wildly in how much indoor air makes it outside. Maybe you can move it out of the flower area and seal up the window. Or, if you're the handy type, you could open the case and do a seal job on it between the evap and condenser sides. Other than that, maybe invest in a portable split A/C unit. Just noticed you're going up to four 600 watt lights, that would put BTUs at around 8200. Don't know how committed you are to the Quadrays, but sealed hoods would probably pay for themselves in a summer or two. If not, the power company would love it if you put heaters and A/C in the same room and let 'em fight it out. Hmm, you might consider doing a drop ceiling with cutouts for the lights. Pull your exhaust from above that and maybe keep the heat moving away from the grow space. Looking forward to seeing what you come up with.

Thank you for the feedback. Your post got me thinking. I think I am going to switch all 4 units to air cooled hoods. However, I'm not sure how I'd run the ducting or where I'd pull the air that I ran over the bulbs from.

Remember, this is my first REAL setup. Still kicking LOTS of ideas around.

 

[IndoorHaze]

Renting or buying? Also, the uninsulated spaces under the roof...is there some existing gable vents or other vents up there? What's the climate like there?

You have a lot of deliciously tough decisions ahead. Some obvious things...those windows will have to be lightproofed, as well as the A/C units. Anything you exhaust may produce a heat signature.

If you're able to do some mods to the attic area that will help. Is there a stairwell up to the garden level? Can you access the areas under the roof that are on the sides of the garden space?

 

[420fied]

Renting or buying? Also, the uninsulated spaces under the roof...is there some existing gable vents or other vents up there? What's the climate like there?

You have a lot of deliciously tough decisions ahead. Some obvious things...those windows will have to be lightproofed, as well as the A/C units. Anything you exhaust may produce a heat signature.

If you're able to do some mods to the attic area that will help. Is there a stairwell up to the garden level? Can you access the areas under the roof that are on the sides of the garden space?

Bought and paid for. No reason for anyone to come calling. I have added a drawing to help our discussion along. There are two roof vents right over top of where I would like to place my lights. All I have to do is cut holes and vent to them. That space is basically a little attic on top of a big attic and I blew insulation in. I'm sure it'll be steaming up there in the summer.

I can seal off everything if needed or I can bring in passive air from the crawl space since it'll be the coolest outside air I can pull from. Is that sound thinking? Obviously, I will make sure everything is light proof. I can do any mods to the attic space that need to be done and I am open to suggestions. You can see on the drawing where I want to place my lights. There are two existing roof vents just above them. I'm just puzzled as to how I'd cool the hoods and scrub the room with a carbon filter. There seems to be so many options.

Yes, there is a stairwell leading up to the garden. Yes, I have access to the dead space on the sides of the room as there are access doors cut into the knee wall on each side of the room that I can crawl through. Notice the light grey lines. That's the ridge line and the edges of the actual roof. I have never been in this space in the summer but it's basically an attic so I'm positive that the air in the dead space/eve is scalding hot. In fact, I know it will be because I insulated it. It's about 8 feet from the knee wall to the eves in the dead space and you have about 4' of headroom when nearest the knee wall. The roof has a steep pitch(likely 10/12) so the headroom decreases rapidly as you move out toward the eves. If you crawl in through the access door, you have about 4' of head room. Insulation has been blown in.

I want to tell you that I really appreciate your help/thoughts. Now that you've seen the new drawing and know a little more do any ideas come to mind?

 

[420fied]

Here's another drawing which gives you a perspective of how it looks right now. Imagine you're standing in the veg room, looking into the flower room.

*It's 8' from floor to ceiling in the flower room. I have approx 1550cu ft that I have to clean. 1150/5= 310cfm needed to clean the room in 5 minutes. I'd need 516cfm to exchange the air in the room every 3 minutes. I'm guessing it'll take a 6" or 8" fan/filter combo?
*The knee wall is approx 4' tall and then the inside wall angles towards the ceiling. There's some room in the dead spaces to the sides. You have approx 4' of headroom nearest the knee wall and then the steep pitch of the roof quickly eats up your space as you get out towards the eves.
*There is approx 3' of space on top of the ceiling. Of course you know there are two, existing roof vents in place there.

Remember, there's no central air in this space.

 

[IndoorHaze]

I think pulling air from the crawl space is a great idea. Might want to get a HEPA grade filter to prevent mold.

My concern on venting is mostly for winter time. I asked about gable vents for a good reason. Just to be clear, here's a photo of one:
https://www.cellwood.com/dealersupport/beauty shots/low-res jpegs/gable_vents.jpg

With one of these in each end of the "attic" space over the grow, any passing breeze would vent the attic, and you can dump air into the attic instead of directly out the roof. This would provide a big plenum to diffuse heat, and would be enhanced if you insulated the roof over the attic. The insulation would conceal any hot spots over your vent into the attic from passing aircraft using IR. It would also lower the heat load in that space in the summer. Smaller ones in the side spaces would also reduce heat load.

If you're really slick, you could recover the waste heat from the lights in winter time to help warm your house or garden.

So a possible solution would be, install a duct from the crawl space to the garden. At the point where it enters, split it into two ducts, one for the hoods and one for the garden.

Put a fan at the beginning of the run to the hoods so any air leaks will go into the garden. Push air through the hoods and into the attic area in summer, and into the garden in winter.

Hang your carbon filters wherever it's convenient and exhaust this air into the attic.

Re: light proofing, not to beat a dead horse, but some window air units also bleed light too.

Hope this gives you some useful ideas. I will probably never get to set up a large grow, so kibbutzing your planning has been fun.

 

[420fied]

Thanks for the advice on the HEPA grade Filter. I will definitely be doing that.

Yes, there is a gable vent in the space above the ceiling and the roof. It's in the exterior wall(the same one the window sits in) and within 10 feet of the two roof vents and I'm almost certain there's one on the other end. If there isn't, there will be. I never even thought of that. Thank you!

Insulating between the roof rafters themselves is a good idea and something I had thought about. As far as the side spaces go, I'll have to take another look to see if they're vented in any way. If not, I will try and find a way to vent them on each side.

Aircraft can't shoot IR into your home without a warrant can they?

I understand bringing up air from the crawl space but I'm having a hard time envisioning the split you mention.

I understand you want me to split it and have a duct for the lights and a duct for the garden. As you can see, I'd like to have (2) light units side by side So how would I cool 4 hoods with one duct? Wouldn't I have to split the duct and have each one cooling a set of lights? Would it be smarter to line my lights up single file? That would eliminate that problem. Are you sure I wanna push air through the fans? I admit I know nothing but I thought I had read that you want your fans to be pulling instead of pushing. Wouldn't the better idea be to place the fan above the lights at the ceiling and pull the air coming from the crawl space over the lights and blow it into the small attic space on a dedicated run of duct? Any light leaks would still be captured in the room.

Gotcha on the carbon filter.

I know some window AC's leak light.... trust me I know. I will make sure that isn't a problem.

Here is how I envision it in my head.

Thoughts?

 

[IndoorHaze]

It's true that the LEOs can't use IR to search for grow ops. But most air ambulances operating at night use IR for navigation, and if they happen to see a heat plume they might tip off the police. I have no solid evidence to back this up, but I do know for fact our local ground EMS people have tipped off police to grows they find when on medical runs.

Re: fans, the push or pull issue is one of those "facts" that circulate in the 420 community with no scientific basis.

For me, the problem is, if you pull air though the hoods, any minute air leaks will suck in bud stench which will go outside with your exhaust. Pushing air eliminates any chance of this. For this same reason, I always butt my fan up to the filter and seal with tape, so any ducting is under pressure and any leaks stay in the garden. I take it as a given that all ducting has pinholes in it somewhere.

From what I have seen of your garden, you -could- put all 4 lights in a line and not lose any illumination. The only drawback to this is the last couple of lights are not going to get cooled very much. I think a Y will provide better cooling for each pair of lights, but it really comes down to how many fans you can budget. One duct from the main to the vicinity of the lights, then a Y with one fan on each leg, pushing through the lights. Each pair would need it's own exhaust to the attic. You could still line 'em up with creative ducting if that makes your garden more convenient for the space.

 

[420fied]

Good feedback on the IR. You can never be too safe. I was telling my wife this isn't like a First Person Shooter video game. I don't get to re spawn if they kill(catch) me so we have to set it up right the first time.... lol.

Good info on the push/pull debate and the stench issue. Pushing it would definitely eliminate any chance that odor gets sucked out. I agree with you that there is most likely pinholes in the ducting.

I see your point about the last couple of units not getting cooled with the straight line setup but all the hoods lined up together will only encompass about 8'. This guy pulled off the straight line setup with a much longer run.

The less fans running the better.

Your help is very much appreciated. Think we're gettin' close?

 

[420fied]

I keep amending the plan as our discussion evolves. Here's where we stand.

Now, let's talk passive intake. I know that area of the intake needs to be equal to the area of the fan that sucks the room air through the carbon filter, correct?

 

[IndoorHaze]

This guy pulled off the straight line setup with a much longer run.
...
The less fans running the better.

Your help is very much appreciated. Think we're gettin' close?

Pretty impressive setup. Try it with one and, if needed add one later. I think we've about got it nailed down.

BTW, it's been a pleasure.

 

[IndoorHaze]

Now, let's talk passive intake. I know that area of the intake needs to be equal to the area of the fan that sucks the room air through the carbon filter, correct?

That would be ideal, but if it isn't possible, air [and water] will speed up or slow down as needed depending on the pressure differential. The trade off is noise and some small loss of cfm. The closer you can get to a match will pay off in less duct rumble. But if you have trouble finding a path for an 8" duct from the crawlspace, you can sub a smaller one.

You -could- fab up a square duct out of foamular and mount it in a corner of the stairwell, make it look like an architectural column, paint the same color as your walls, assuming the stairwell would accomodate this. Or maybe there is another path up that would work with this treatment, maybe in a corner of a room on the lower floor. If it's noisy, sheet rock over it. Anyone asks, its the sewer vent.

 

[420fied]

Pretty impressive setup. Try it with one and, if needed add one later. I think we've about got it nailed down.

BTW, it's been a pleasure.

Thank you so much for brainstorming with me. I have the power turned on for us.

+ Reps to you for your help.

 

[420fied]

That would be ideal, but if it isn't possible, air [and water] will speed up or slow down as needed depending on the pressure differential. The trade off is noise and some small loss of cfm. The closer you can get to a match will pay off in less duct rumble. But if you have trouble finding a path for an 8" duct from the crawlspace, you can sub a smaller one.

You -could- fab up a square duct out of foamular and mount it in a corner of the stairwell, make it look like an architectural column, paint the same color as your walls, assuming the stairwell would accomodate this. Or maybe there is another path up that would work with this treatment, maybe in a corner of a room on the lower floor. If it's noisy, sheet rock over it. Anyone asks, its the sewer vent.

I think I can find a way to run an 8" duct from the crawl. I'm going to start a new journal that documents this build and I hope you'll look for it as you've helped me a great deal.

 

[dragontoker]

I changed your pic a little bit to show how the insulation should be ran and the air gap that should be left between the roof decking and the insulation. Does it make sense.

Very quiet inline that you wont hear from the first floor whatsoever and can be easily controlled with a speed bully variable control. Panasonic whisperline inline fan.

 

[420fied]

I changed your pic a little bit to show how the insulation should be ran and the air gap that should be left between the roof decking and the insulation. Does it make sense.

Very quiet inline that you wont hear from the first floor whatsoever and can be easily controlled with a speed bully variable control. Panasonic whisperline inline fan.

Thank you. It makes sense. I have heard good things about the Whisperline so I will definitely be looking at them.