How do you provide fresh air for plants in an air conditioned room?

[hush]

My last thread seems to have run out of gas, so I've rephrased my current question of the moment, in the hopes that it will spark more discussion.

Here's a brief summary of what I'm doing:

I have a decently-insulated utility room on the back side of my house that is currently not air conditioned. This room never receives any overhead sunlight, as it is covered by tons of old-growth Live Oak trees. Because of the constant shade it is under, it never climbs up much higher than about 88-90 degrees, even though the temperature around here actually gets up to the upper 90s. But that is obviously still too hot to grow plants, especially after adding a 1000w HPS, lol, so I know I have to air condition the room.

But what I am not understanding is HOW THE HELL DO YOU GIVE FRESH AIR TO YOUR PLANTS IN AN AIR CONDITIONED ROOM? The obvious answer is to install an active exhaust (or intake) in the air conditioned room, but then that makes the air conditioner work too hard (possibly too hard to even be effective anymore?). So then the other obvious answer is to seal the room and use CO2, instead of fresh air. But that requires a lot more expense in terms of buying equipment, monitors, controllers, and so forth. Not too appealing to me, quite frankly.

So what do I do? The way I am currently seeing it, I either have to face the fact that the only way to make an air conditioned room work is to inject CO2. Or, I have to accept the fact that in order to use an air conditioner in this room, I will have to also make sure that fresh [90 degree] air is constantly seeping into the room, making the AC work harder.

I would like to get this project started this coming up weekend, as soon as I can figure out what to buy. All I know is I definitely need air conditioning in that room. But I would prefer not to use CO2 at the moment. Is there such a thing as a happy medium? Where I am only drawing enough fresh air into the grow room that the plants need, while not entirely clearing the air in the grow room every 5 minutes or whatever?

I understand that window bangers don't exchange air with the outside, so if I went that route (the cheapest one, of course), I would certainly need to provide fresh air. But I'm kind of understanding that some portable air conditioners, especially the single hose style ones, actually create negative pressure which would mean fresh air would be pulled into the room through the cracks all around the room. Would that even be effective? Also, if it matters, I plan on running an air-cooled tent inside of this room. This way light proofing and odor elimination would be easily dealt with.

I'm so confused!!!! I need help!!!!!

 

[vertigo0007]

If its connected to your house could you pull "fresh" air from the house? Window units will drip weed scented water outside your house. Another consideration would be portable units leak, or billow, smell in their exhaust.

 

[BullnAChinaShop]

If you go portable they make dual hose units, 1 to pull in fresh and 1 to exhaust hot. So you pull in hot air from outside, ac spits it out cold.

 

[hush]

^ That's not my understanding of how the dual hose portables work... as I understand it, both hoses only affect the "hot side" of the air conditioner. One hose takes in fresh outside air to exhaust the hot air with. The cold side of the air conditioners just recirculate the air in the room. So without reintroducing fresh air into the grow, the AC will eventually just be recirculating CO2-depleted cold air.

Can anyone confirm this for me?

 

[7 Willows]

fresh air just means fresh co2 for them. Have to producem/pump

 

[hush]

vertigo007, that is a thought I had, too. It would be a bitch to accomplish, meaning I would have to go rent an expensive diamond core saw from Home Despot, in order to drill through the concrete block. I was hoping to avoid that. But it is still being considered. Thank you for the suggestion.

 

[BullnAChinaShop]

Wow, looks like I was misinformed on that one. Thanks for the clarification. So yea your gonna need intakes (which is going to really make that AC work) or a CO2 supply of some sort.

 

[BullnAChinaShop]

Supplying CO2 would let you run a little hotter as well, so the AC wouldn't have to work as hard to maintain.

 

[BullnAChinaShop]

Another option would be to take a window banger and build one of those boxes around it. Then you could box off the hot air intake and pipe it to the outside. At least this way you won't be letting warm air into the room itself.

 

[hush]

^ I've looked into this, as well. It turns out, when you properly box off a window banger, you end up with essentially a dual hose portable A/C, which will just recycle the cold air in the garden, eventually depleting the CO2 within (unless fresh air or CO2 is introduced). Which leaves me right in the same spot. How do I bring fresh air into the garden without exhausting all that expensive refrigerated air?

The more I think about it, there are really only 3 options:

1) Seal the room and inject CO2, making the problem an obsolete one

2) Bring fresh air in from the 90 degree outside air

3) Bring ~75 degree fresh air in through the concrete wall, from the house


Option 1 is the "correct" way, but very expensive and will always require me to have to go to the welding shop and refill my CO2 tank. Option 2 is the absolute simplest way, but I fear it will prevent the air conditioner from ever properly doing its job (or cycling off, for that matter). And option 3 requires knocking a big ass hole through the wall of the master bedroom, which will be unsightly, PLUS, it would affect the central cooling abilities of my house A/C system. (Right?)

 

[vein5]

I just got a dual hose ac for my small room and tried everything to get fresh air while keeping it cool. After days i threw my hands up and am sealing the room right now, and am about to go out and get a co2 control. Summer sucks for growers

 

[vein5]

I tried cycling my exhaust and for me that did not work bc the passive intakes just leaked all the cold air out. Last night my ac ran all the time for the most part. If you find a way please pm me!

 

[BullnAChinaShop]

Yea I shut down for the summer or just work on some seed projects. Too expensive to cool.

 

[hush]

Damn!!! It's not looking so good for me. Maybe I am going to have to seal it off afterall...

If I do go the sealed route, would it make sense to use a CO2 burner for generation if I live in such a hot climate? Or am I going to have to use bottled CO2? It sucks either way, because it means extra crap to buy and constantly maintain. I already have a CO2 regulator and solenoid from one of my aquariums. But I only have a 10 pound tank, which means I would have to visit the welding shop multiple times a week, or I would have to buy a bigger tank. That means more money spent.

Arrrrrrrgh!!!!! I hate heat!!!!!!! No wonder hate and heat are anagrams.

 

[Snook]

^ I've looked into this, as well. It turns out, when you properly box off a window banger, you end up with essentially a dual hose portable A/C, which will just recycle the cold air in the garden, eventually depleting the CO2 within (unless fresh air or CO2 is introduced). Which leaves me right in the same spot. How do I bring fresh air into the garden without exhausting all that expensive refrigerated air?

The more I think about it, there are really only 3 options:

1) Seal the room and inject CO2, making the problem an obsolete one

2) Bring fresh air in from the 90 degree outside air

3) Bring ~75 degree fresh air in through the concrete wall, from the house


Option 1 is the "correct" way, but very expensive and will always require me to have to go to the welding shop and refill my CO2 tank. Option 2 is the absolute simplest way, but I fear it will prevent the air conditioner from ever properly doing its job (or cycling off, for that matter). And option 3 requires knocking a big ass hole through the wall of the master bedroom, which will be unsightly, PLUS, it would affect the central cooling abilities of my house A/C system. (Right?)

In the long run, the CO2 would be the least expensive. IMO. lower electricity cost, not having to fix the hole in the block wall later and after set up cost, cost is only the CO2.. sell one or 2 of the 30-40 OZs youll get first harvest, and pay yourself back. where you gonna dry the havest? 70ish*F/50%ishRH.. it would be too hot in da grow room, no ventilation/air.

 

[hush]

^ Good question! I will be drying the harvest inside my house, where I've currently got my 400w tent setup. I have a large carbon filter scrubber in the closet of that room so it's perfect.

Thanks for the tip on the CO2. I might as well go the CO2 route. It seems like the path of least resistance. No wonder I spent the past week and a half failing at Google searches such as "air conditioned grow room fresh air." It's because you really can't do AC unless it's also a sealed room.

 

[Treetroit City]

Well I'll add something here. You don't need to spend a fortune to have co2.

You do not need a fancy meter/monitor, I've done without for many a year just fine. All I use is a #20 tank(15 bucks a fill) and a regulator with a recycle timer($150?).

A lot of people think if you are going to get involved with co2 you need a meter to keep it at 1500 ppm which will of course go through tanks very fast.

But if you just want to insure "fresh air" then all you need is 400 ppm. Is it ideal? Maybe not but your ladies will not mind one bit.

I keep my 12x13 room at 500-1000 and have been on this tank since 4/20, so at least a month a tank.

Now I will be upgrading to a fancy meter/monitor after a crop or two but this setup has been with me for 13 years now keeping ladies happy, or at least not starving.

And when I do upgade, this setup will go in my veg room which has no "fresh air" but has been growing plants just fine without.

 

[hush]

That looks like the size tank I have! What size is that tank?

 

[Treetroit City]

That's a 20 pounder, it's a big plant.

After I finished my last post I got to thinking. My veg room is pretty well sealed up except for the window AC which probably provides a little air exchange.

Seems that my plants are doing good in this fresh air lacking room. Good and green, healthy and good growing rates. Clones root in 7-10 days no problem.

Hey you recognize that permanest tray don't ya haha? Thanks for the reminder a few months back.

While I would never really recommend someone grow with lack of fresh air/co2, I will just say it can be done if needed.

 

[LouDog420]

I run a tent within a room mainly managed by your usual intake/exhaust, but have supplemental AC for the hottest times of the year, no CO2... If it was me, and I didn't have CO2 easily available, I'd....

Cut a hole for intake from the house. Gotta have a source of fresh air, and trying to bring in the outside air isn't going to cut it because it's too hot and humid... No way to get around that without CO2...

I run a filter box that holds my carbon filter, ballasts, and the exhaust for my portable air conditioner. Using the room as a lung room, I have an intake coming in and feeding cool air. Air then runs through my tent, to the filter box, and out through the exhaust. No doubt I'm exhausting air that has been cooled by the portable, but I run it over my bulbs first, extracting heat from the tent, then through my filter box cooling the ballasts while getting scrubbed, then out through exhaust... Gotta figure it's been warmed to a point where it's worth exhausting by then...

Running a 800 watts vertical in a 4x4 plus 250+watts for veg and extras in a 10x10. Temps in the tent stay within 5-6 degrees ambient and I can run the lung room at 70-72 all day long with the portable running occasionally (90-92 outside)... 12000 btu portable. Intake comes from a cold basement though so that helps a lot. Veg area also isn't closed off so it's shooting out hot air into the lung room constantly...


So the airflow would go something like this, if it was me...
Intake (House) --> Lung room --> Tent -- > Filter Box --> Carbon Filter --> Exhaust

And the dual hose portable air conditioner goes something like this
Intake (Outside) --> Portable Air Conditioner --> Filter Box --> Carbon Filter --> Exhaust


That way all air exhausted is getting scrubbed, only requires a single exhaust, fresh air comes in cool from the house, and the air conditioned air is utilized to its fullest given the scenario...

Good luck!