Intake and exhaust 10x20

I am still debating whether or not I do one 10x20 grow tent or two 10x10 grow tents. Each light will cover a 4x4 and have 9~ or so plants. I have 8 of the HLG 550 v2 quantum boards. I will not be running co2 in a grow tent.
I am trying to figure out the best way to scrub the air and vent the 10x20 grow tent so my neighbors dont smell it. Here are my questions!

Would I need an intake fan or just a passive intake with an exhaust would be fine?

Since the tent is so big do you think I would need a standalone carbon scrubber in the tent on top of the one used in the exhaust system?

If I go the 10x20 route since the tent is so big would you recommend putting an actual AC unit inside the tent? I feel like if I went 2 10x10s could avoid putting an AC inside each tent and just cool the room they are in, but I dont know if a 10x20 would be too big to passively cool?

Also if I get like a dual duct portable AC for the 10x20 tent, wont it exhaust stinky air outside the tent that I would have to scrub too?

With adequate scrubbing in the tent you will hardly smell the weed standing right next to it.

I would just set the AC in the tent. Going with one large tent will minimize the costs of AC and dehumidifiers and such.

Since you will have an AC in there the exhaust is only to bring in fresh co2 correct? I don't see a need to have an intake fan, just a passive intake. The AC, depending on model may exchange enough air to keep CO2 levels up provided a passive intake.

I’ve seen people run mini splits in larger tents, if that’s not an option I saw a post on here the other day on sealing up a portable AC. Otherwise you will most likely vent some smell. I’d say if you went with two 10x10 and flowered one at day and one at night you should be good as long as your ambient temps aren’t too high. I think your at about 15000 btu to cool 8 550s(the btu rating on portables is often not correct go bigger than this number for a portable.) if you have a window in the room the tent is in a window ac would be great option. Since it will be outside the tent won’t have to worry about smell as long as your exhaust is scrubbed.

Renfro said:

With adequate scrubbing in the tent you will hardly smell the weed standing right next to it.

I would just set the AC in the tent. Going with one large tent will minimize the costs of AC and dehumidifiers and such.

Since you will have an AC in there the exhaust is only to bring in fresh co2 correct? I don't see a need to have an intake fan, just a passive intake. The AC, depending on model may exchange enough air to keep CO2 levels up provided a passive intake.

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I do not want to run a closed tent and I do not want to run CO2. If I put the AC inside the tent and did not run CO2 smell with vent out the tent with the ac right?

Apalchen said:

I’ve seen people run mini splits in larger tents, if that’s not an option I saw a post on here the other day on sealing up a portable AC. Otherwise you will most likely vent some smell. I’d say if you went with two 10x10 and flowered one at day and one at night you should be good as long as your ambient temps aren’t too high. I think your at about 15000 btu to cool 8 550s(the btu rating on portables is often not correct go bigger than this number for a portable.) if you have a window in the room the tent is in a window ac would be great option. Since it will be outside the tent won’t have to worry about smell as long as your exhaust is scrubbed.

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I just think it would be a pain to do a whole mini split in the tent. I either want to put a portable ac in the tent, or just a portable ac/window unit outside the tent and bring fresh air in. I just do not think co2 is the way to go with a grow tent.

learningthebasics27 said:

I do not want to run a closed tent and I do not want to run CO2. If I put the AC inside the tent and did not run CO2 smell with vent out the tent with the ac right?

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If you don't run supplemental CO2 you must get fresh air into the tent as the plants will consume the CO2 in the tent and need more.

Renfro said:

If you don't run supplemental CO2 you must get fresh air into the tent as the plants will consume the CO2 in the tent and need more.

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I was looking at a double duct portable air conditioner to throw inside the tent if I went that route. It would exhaust the warm air outside the tent. Is it better to buy a double duct ac and throw it into the tent or just cool down the room the tent is in?

It would indeed be more effective if the AC is inside the tent. If you aren't going to add supplemental CO2 then you don't need a double hose AC because you need some air exchange to maintain the CO2 levels inside the tent equal to those outside the tent, the plants will be consuming CO2. A single hose unit and a passive intake on the other side of the tent would bring enough fresh air through the tent to maintain CO2 levels.

If you have enough scrubbing capacity inside the tent you wont smell the weed standing inside the tent. Plus the scrubbers can be used to move air in the tent. Just put an adjustable elbow on top of the blower to direct the flow.

Renfro said:

It would indeed be more effective if the AC is inside the tent. If you aren't going to add supplemental CO2 then you don't need a double hose AC because you need some air exchange to maintain the CO2 levels inside the tent equal to those outside the tent, the plants will be consuming CO2. A single hose unit and a passive intake on the other side of the tent would bring enough fresh air through the tent to maintain CO2 levels.

If you have enough scrubbing capacity inside the tent you wont smell the weed standing inside the tent. Plus the scrubbers can be used to move air in the tent. Just put an adjustable elbow on top of the blower to direct the flow.

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Awesome! So basically as long as the tent is scrubbed correctly you wouldnt smell anything coming from the AC exhaust either

I think it’s kinda optimistic to say just by running a recirculating scrubber that your ac exhaust won’t stink. The only way I’ve ever been able to get no smell leaking is run negative pressure meaning every bit of air coming out of that room is pulled thru the filter. Since your not using C02 I’d just go with a window unit to cool the room the tents in. Window units are cheaper to buy, use less electricity, and will get the job done. I think everyone who has grown has used a portable at some point but they really just don’t work very well.

I might run a Window unit, and dehumidifier for the entire room.
Sealed room. No Co2. Scrub inside tent.

Use cycle timer to schedule intake/exhaust fresh (filtered) outside air to maintain Co2/O2 for the entire room.

Normally Window ACs do not bring in fresh air from the outside. Nor do they blow inside air outside. (Odor)

Portable ACs seem like they create more problems than they solve. But I understand sometimes its the only option.

Apalchen said:

I think it’s kinda optimistic to say just by running a recirculating scrubber that your ac exhaust won’t stink. The only way I’ve ever been able to get no smell leaking is run negative pressure meaning every bit of air coming out of that room is pulled thru the filter.

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Well I am advocating a couple LARGE scrubbers. Works for my grow and it's pretty big and has a stinky strain. So I believe that if the OP doesn't undersize the scrubbing he will do well.

Anyway he chooses its gonna be costly. Either spend money on scrubbers or spend money somewhere else like a minisplit. Scrubbers will keep the home from smelling and thats a bonus.

TintEastwood said:

Normally Window ACs do not bring in fresh air from the outside. Nor do they blow inside air outside. (Odor)

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I dunno, many people have complained that window AC units leak odor, never ran one in a big grow without a lot of scrubbing so I don't know for sure.

Renfro said:

Anyway he chooses its gonna be costly. Either spend money on scrubbers or spend money somewhere else like a minisplit. Scrubbers will keep the home from smelling and thats a bonus.


I dunno, many people have complained that window AC units leak odor, never ran one in a big grow without a lot of scrubbing so I don't know for sure.

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Indeed. No doubt about it, costly.

Before my sealed room, I was sick and tired of thrashing temps and humidity.

So far no outside odor with my lil 6k Amana. But I'm small time hobby 4x8x8. ( working on new 4x4 veg box)

I’ve run window units in a lung room(basically large room that has a couple tents or small built rooms) and as long as there was negative pressure pulling out of the room thru a filter all was good. I see people placing them directly in their grows rooms tho and I’d say that way they do let some smell out if had to guess. I mean if the water coming out of a mini split can carry the smell outside then I’m pretty sure the same would be true for a window unit. By placing whatever AC you go with outside the actual grow room I’d say you won’t have to worry as long as your tent exhaust is well scrubbed. If your not using C02 and said u didn’t want to then I would for sure use negative pressure to control the smell as it’s the most effective way.

Apalchen said:

I’ve run window units in a lung room(basically large room that has a couple tents or small built rooms) and as long as there was negative pressure pulling out of the room thru a filter all was good. I see people placing them directly in their grows rooms tho and I’d say that way they do let some smell out if had to guess. I mean if the water coming out of a mini split can carry the smell outside then I’m pretty sure the same would be true for a window unit. By placing whatever AC you go with outside the actual grow room I’d say you won’t have to worry as long as your tent exhaust is well scrubbed. If your not using C02 and said u didn’t want to then I would for sure use negative pressure to control the smell as it’s the most effective way.

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Do you think in a 10x20 tent you could sufficiently cool the tent just by cooling down the room?

TintEastwood said:

Indeed. No doubt about it, costly.

Before my sealed room, I was sick and tired of thrashing temps and humidity.

So far no outside odor with my lil 6k Amana. But I'm small time hobby 4x8x8. ( working on new 4x4 veg box)

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So you have your room sealed, then a grow tent inside that sealed room? I was just going to put like a 10x20 tent in the living room. I mean I could possibly do two 10x10s in the master if it would be more efficient to seal a master bedroom than a living room.

learningthebasics27 said:

So you have your room sealed, then a grow tent inside that sealed room? I was just going to put like a 10x20 tent in the living room. I mean I could possibly do two 10x10s in the master if it would be more efficient to seal a master bedroom than a living room.

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Yes. Unfortunately, my grow room is in my 2car garage. Where temperatures and humidity are a nightmare. 120+ in the summer! I shut everything down for 3 months.

Sealed a must.
In fact, I framed out a new veg box today. Also sealed, will share the air from flower box.



Don't fail me 6k Amana! (Previously a doggie door.)

learningthebasics27 said:

Do you think in a 10x20 tent you could sufficiently cool the tent just by cooling down the room?

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I’ve never tried air cooling anything that large, but the math should be the same. 3.412 btu per watt of lighting. 550x8=4400 watts but let’s call it a min of 5000 watts because of other equipment. It takes 3.41 but per watt so 3.41x5000= 17050. So the min size AC I’d go with would be 18k btu. I’d go bigger than that tho but I’m not used to led. I am getting a 2 ton mini for 4K watts.

It would def be cheaper to cool 2 10x10 tents run on opposite schedules. Then you only cooling 2200 watts at a time. At that point depending on your home hvac system and or ventilation you use you could possibly not even need extra AC unless it’s really hot where u live. I successfully air cooled 2150 watts in a 4x8 all winter just had to keep the house set on 66 and highest temps I got was 81 and that was with venting back into house for heat. I did close the damper for the hvac to the room it’s in so it didn’t get heated by furnaceand I open it when have AC on. I have dropped down to 1830 watts for now as it’s warming up outside but won’t be a problem in couple weeks when get the mini installed.

The only problem with two tents is you have to buy 2 of everything and can add to intial cost.

Apalchen said:

It would def be cheaper to cool 2 10x10 tents run on opposite schedules.

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I dunno about cheaper, each room would need duplicate equipment like dehumidifiers, AC units (albeit smaller ones), environmental controllers, scrubbers... It may be easier to cool one large room running at night.