NEW ROOM... VENTILATION ADVICE

[LastHurrah]

Hey Folks,

So I'm putting this room together:

I've got a few things arriving in a couple of days that should allow me to complete this build. It has been worked and re-worked on paper and in my head for months and it's finally getting done.

Does the ventilation plan look okay to you veterans? No supplemental co2 (yet).

I'm pulling outside air into the room through a couple of 8" filters that are right next to the 10k btu wall a/c.

The air is exhausted through an 8" filter and fan (speed controlled) into the adjacent garage. I plan to just set the a/c for whatever temp is required to keep the canopies at 80 degrees when lights are on. Is this right? When lights are off, the a/c set at the same temp will bring the temps down further giving me "cooler nights" I think. Is this right?
I'm not so sure about air exchanges. 846 cubic feet in there. Air exchanges twice per minute would require a lot more air flow than I can muffle.

How many air exchanges per hour does everyone suggest? I'm prepared for the onslaught of opinions, and want to hear them. I'll sift through all the opinions.

I know I can get a bigger fan/filter so the fan can run at lower speed and be quieter. Should I go that route?

Thanks for your help. I'll have a nice little show to put on once this room is buttoned up in the next week. Hope y'all check it out.

LH

 

[Shmavis]

Dig the detail of your plan, LH!

So clearly I’m no expert on this subject , but I noticed you didn’t mention the CFM rating of the Hyper Fan. Is it 710, like the 8” one I found on Amazon? And do you have any idea where it’s at when it’s being dialed down for volume purposes?

I have a 6” Can Max Fan with a built in controller and it gives CFM rating for each speed control setting, of which there are three. Does yours let you know the rating at varying speed settings?

If you’re happy with the sound level now, I wonder if instead of getting a bigger fan and dialing it down you could go active instead of passive on your intake... maybe a six inch dialed down for intake would achieve a greater exchange rate... I dunno.

I’ve been digging through some old PDFs. Haven’t run across it yet but I could’ve swore that, at least circa early 2000s, that it was recommended to be able to exchange the room’s air within five minutes time, at the most. So a room of 500 CF would require a fan of at least 100 CFM ... but this may be a false memory. Moreover, it seems somewhat irrelevant given DHF’s recommendation of twice per minute, which he’s found ideal through actual experience.

And I take it you’re exhausting 24/7?

Hope y'all check it out.

I will be there!

 

[plutosmoke]

can you chime in more on your seasonal temps? If during the summer time your outside is in the 90-100, which these days are the norm, I can see your ac might have a very hard time keeping temps cool with air being exchange also.

Also, how sealed is this room? if the room isn't completely sealed, you might consider not using the intake from outside and let the scrubber fan create a negative pressure that will suck small amounts of air from the cracks of the room, that way the AC won't constantly be cooling the high temps from outside(if its hot).

 

[LastHurrah]

Thanks for the replies guys!

Shmavis - The speed control of the hyperfan is variable (35-100%), so I don't know the cfm's. I'm mostly interested in keeping acceptable noise levels, so adding a powered intake isn't going to help there. I'm looking at some cheap anemometers (sp?) to measure the wind speed being exhausted. Then I can use the speed controller with greater precision. Also saw a nice co2 meter that can control a regulator/tank if/when I decide to add them. Been doing some reading and air exchange recommendations range from once per minute to once every 3-5 minutes. With all due respect, DHF's "twice a minute" advice seems like it's excessive.

plutosmoke - i'm inland NorCal and it's hot as f*ck here in the summer... easily 95+ for the whole of July and not much better in June and August. The room isn't completely sealed. In fact, I wonder how folks are stopping "any" air from entering around the entry door. I was going to use air from inside the house for intake, but wouldn't be able to conceal it nicely. I haven't picked up the a/c yet and think I may bump up the btu's.

LH

 

[Granger2]

Twice/minute helps a lot with temp control. Once every 5 mins is enough for just maintaining fresh air. Good luck. -granger

 

[PNWCannaman]

Im no pro but a few thoughts...

Passive intake near A/c exhaust is no Bueno, it may suck that warm air in. Defeating purpose of A/C.

Is there a reason why the exhaust is not directly vented out of your garage?

I would advise exhausting your hyper fan out of the garage. Gable vents work well and are easily adaptable to ducting exhaust.

Are the 600s air cooled or open hood? I'm assuming open hood.

With the air con and 8 in fan you should be just fine as long as your not pulling in hot a/c exhaust air...already stated but important.

I think the a/c may be over kill because an 8 in fan will cool those 4 fixtures even if they are open hood with no problems at all.

Espessially if you run your lights on at night to pull in cool air. Save money on the a/c bill because You bought a good enough fan to cool that amount of lighting.


Heres an idea, if you move the trays together you will get benefit of light overlap and will still have two small walkways to water on each side. plus the fan could be centered over the array of lights helping pull heat from all 4 lights equally. and final changes would be having no a/c and swapping your hps to the intake side as it would be cooler and venting that 8 inch exhaust directly out of the garage. That would be how I would set it up but like I said I'm no pro just a hobbyist with a few years of exp...


Hope that helps!
Peace

 

[LastHurrah]

PNW - thanks for the advice. I'm mulling it over and going through some more ventilation threads today. I may just break down, seal up the room, and run co2 from the start. I think I'll be better off. You got me with the "passive intake near a/c exhaust pulling in warm air". Are sealed rooms actually "sealed"? I can't imagine that "no air" gets in sealed rooms but I've never actually tried to seal a room and use co2. Uncharted territory for me.

LH

 

[Shmavis]

PNW - thanks for the advice. I'm mulling it over and going through some more ventilation threads today. I may just break down, seal up the room, and run co2 from the start. I think I'll be better off. You got me with the "passive intake near a/c exhaust pulling in warm air". Are sealed rooms actually "sealed"? I can't imagine that "no air" gets in sealed rooms but I've never actually tried to seal a room and use co2. Uncharted territory for me.

LH

Hey LH,

I was thinking about mentioning this before, but I didn’t think it would be an option, as I thought you were so close to getting ready to kick-off.

I also think it would be a good idea to go with CO2.

I can only speak to my experience; and in hindsight I wish I would’ve gone with CO2 right-off-the-rip... instead I heeded the advice as laid out in so many of the books... about waiting till you’ve repeatedly had success without it... and by doing so came to expect certain outcomes. Once you add CO2 that all changes dramatically, or at least it did for me — there is a whole host of new variables introduced. These were changes in conditions that I would’ve rather dealt with straight off... heat and humidity, explosive growth rates that altered watering and feeding schedules...

This all goes back to my point about dialing-in a room. If you’re going to employ the scientific method, you need a constant variable, i.e., clones, from which to establish a benchmark. So to a certain extent it doesn’t seem to make sense to wait to add it, unless someone is growing for commercial purposes and looking to push one or two particular strains.

The only time I ever experienced mold was shortly after adding CO2. I was growing a cross of Belladonna x White Widow aeroponically, the height was out of control and the colas so huge that when drying they molded. I eventually realized that I could no longer veg with aero and CO2. I had to take clones directly into flower to control for height.

And now here I am about to seal up my room... uncharted territory for me as well, and I expect to have to make adjustments once I get under way...

The spray foam insulation that I'm going to use is supposed to provide a 100% airtight seal.

Anyway, wordy way to say I’d go with CO2. That is, if you’re pretty sure you’re going to add it eventually; I'd say do it upfront.

Best of luck to you!

 

[Asslover]

PNW - thanks for the advice. I'm mulling it over and going through some more ventilation threads today. I may just break down, seal up the room, and run co2 from the start. I think I'll be better off. You got me with the "passive intake near a/c exhaust pulling in warm air". Are sealed rooms actually "sealed"? I can't imagine that "no air" gets in sealed rooms but I've never actually tried to seal a room and use co2. Uncharted territory for me.

LH

Yes, sealed rooms are actually SEALED. At least as sealed as we can get them
Seriously though, seal it, use co2 in a bottle and use a dehumidifier. Simple. No exhausting or exchanging. As for sealing, I think I'm as sealed as King Tuts tomb once was, but I still run a scrubber just to be safe. Can't be too careful here in the Sunshine State...

 

[LastHurrah]

Thanks Asslover. I made up my mind to seal it "as best as I can" and add co2. Considering this co2 monitor that controls a tank/regulator (http://www.co2meter.com/collections/fixed-wall-mount/products/day-night-co2-monitor-controller). Has a light sensor so "no co2 is disbursed during lights out".

How do you seal the entry door? Weather stripping?

LH

 

[Granger2]

If your getting 95 degrees, bringing in fresh air will not keep your temps low enough. I also don't think a 10000 btu AC will be enough for the lighting you have. Rule of thumb is 5000/1kw.

I doubt that any sealed room is completely sealed. Mine's pretty close, but not 100%. Careful with the offgassing/outgassing from spray foam. Research it. Good luck. -granger

 

[LastHurrah]

I also don't think a 10000 btu AC will be enough for the lighting you have. Rule of thumb is 5000/1kw.

Agreed... upgrading a/c.

Thanks Granger!

LH

 

[PNWCannaman]

1KW = 3500 btu

OP is running 1.8KW

with fans and 5-7a dehuey

10k if sealed well should be like the bare minimum, but a 12-14k+ would be advisable.

You will need an assload of spray foam some silicone gel and few roll of duct tape for our sealing venture. The better sealed the more efficient the a/c, dehuey, and co2 will run.

This to me seams like the wrong move, no offense but you really have everything you will need to grow well. Why keep buying more?
You built a great room.

CO2 isn't just a tank.
FOr a quality setup you will need at the very least a fuzzy logic controller which run a few hundred bucks200-300 plus the regulator which is 1-200
plus the tank itself which depends on size for price but the smaller ones are like 100bucks
so that at least another 500 dollars plus dehuey 200-500 plus weekly 10$ fill
room your size you will need to fill tank once a week maybe every 2 weeks if you have a larger tank. one problem is you will have to fill at the hydro store so in reality you need two tanks so you can swap out right away and fill the empty at store....$$$$$
Or you can get a co2 burner but that's more heat and more a/c needed....
co2 isn't so simple and is so much more money bro
please gain experience using air cooling before the money drop
no offense I just have seen people go down this road and still get less than 1GPW, so why even do it?

Look at sentinel controllers if youre set on sealed, they rock. Here's a couple sites that offer sentinel products...
http://www.growitbest.com/products/sentinel-gps-cppm-4i-fuzzy-logic-co2-controller-4-cs
http://growershouse.com/sentinel-chhc-4i-digital-intelligent-total-environmental-controller

 

[PNWCannaman]

Ok i'll give you an example. I run 1.8kw in a 5x9 tent using a 6"MAX PRO 420cfm at LOW to vent with great success. Last harvest was .78 GPW horizontal grow, with 8 plants that had 4 week veg, I used a coco/soil mix and AN nutes. I had to add a small electric heater 750w to keep night temps up during cold months and it help well with humidity control.

During the summer It does get up to 90s outside here too, but that really is only one crop out of 6....
I just crank up fan to high and set lights to 9pm-9am so I can use cool night air in the summer. Temps are generally low 80s this way.
So in reality one of 6 crops is less quality/quantity but honestly its pretty negligible.
Im not trying to be a dick and really hope im not coming off that way

Im just trying to say run her how you brung her...lol
You really did a nice job planning the build, and I think you could get away with no a/c at all but maybe use it a lil in the summer as a back up if at all..

I think that the co2 in the air outside is plenty because if that's the same air that is growing those 10-12 pound monster plants in your neck of the woods Idk why anyone would need better air(more co2)....

In reality, plants can handle higher temps as long as your air exchange is dialed

People in AZ grow plants outdoors in 100 plus degree temps and still get very nice smoke because they are in a constant fresh air.


just a few more thoughts...
hope something helps!!
peace

 

[LastHurrah]

I think that the co2 in the air outside is plenty because if that's the same air that is growing those 10-12 pound monster plants in your neck of the woods Idk why anyone would need better air(more co2)....

Agreed, but bringing in that air also means bringing in higher than desired temps... which requires a/c. I'm right around Sacramento and it gets hot early in the year (easy 90's in April/May). I'll be needing a/c by the time my sprouts are ready to flower in roughly 6 weeks. I have a good deal on a Freidrich 18k btu that I feel would cover an eventual increase in flower wattage. Too big?

Would the setup improve if I draw air from an adjacent room in the house? I'd still use filters, but that air would be "conditioned" to about 72ish. Would co2 levels be adequate coming from inside the house?

I like Sentinel products too, but do you think the meter I linked to would be sufficient? It controls an optional solenoid and I have immediate access to a good size tank full of co2 through a welder friend of mine. The CHHC is awesome, but is it "really" necessary at 6 LARGE?

Thanks for all the explanations and examples. Keeps me thinking and I generally come up with good plans when I keep my mind focused.

LH

 

[PNWCannaman]

Agreed, but bringing in that air also means bringing in higher than desired temps... which requires a/c. I'm right around Sacramento and it gets hot early in the year (easy 90's in April/May). I'll be needing a/c by the time my sprouts are ready to flower in roughly 6 weeks. I have a good deal on a Freidrich 18k btu that I feel would cover an eventual increase in flower wattage. Too big?

Not too big at all she would be great. I have heard awesome things about freidrich.

Would the setup improve if I draw air from an adjacent room in the house? I'd still use filters, but that air would be "conditioned" to about 72ish. Would co2 levels be adequate coming from inside the house?

I have never done so. I would sugest researching a lung room, so you can pull in fresh air and use your a/c to cool it before it enters the growroom. Then just use standard exhaust, it can even go into your garage/house as long as your lung room is not sucking that air back in...


I like Sentinel products too, but do you think the meter I linked to would be sufficient? It controls an optional solenoid and I have immediate access to a good size tank full of co2 through a welder friend of mine. The CHHC is awesome, but is it "really" necessary at 6 LARGE?

If you want co2 you need sentinel. Quality will never dissapoint. I buy Gavita lights because of quality even tho they are 2x the price of standard lights. Using lung room would eliminate need for extra co2. If im correct the air will be cool, dry, and have adequate co2 levels, perfect for MJ

Thanks for all the explanations and examples. Keeps me thinking and I generally come up with good plans when I keep my mind focused.

LH

LUNG ROOM should be your next search topic.
Like I said I'm no pro, just a hobbyist, I hope that I have helped in some way

 

[Granger2]

Using 72* air from the house is certainly better than hotter outside air, and if there are mammals in the house they are CO2 generators. Good luck. -granger

 

[LastHurrah]

Twice/minute helps a lot with temp control. Once every 5 mins is enough for just maintaining fresh air. Good luck. -granger

Reminder to myself. Thanks Granger!

LH

 

[LastHurrah]

Reminder to myself. Thanks Granger!

Hey folks. I thought I'd drop a note that this grow is actually about to get going. Just about done with the finishing touches on the room. Stop on by.

LH

 

[bearminimum]

Hey folks. I thought I'd drop a note that this grow is actually about to get going. Just about done with the finishing touches on the room. Stop on by.

LH

Good read. Good luck. Pics or it never happened