Portable A/C question

Hi folks,

I have a questions about those portable A/C units, the ones that have two ducts (intake & exhaust) to the window.

What I'm wondering is, do they exhaust the air from inside your room? Or do they only exhaust the air that they bring in from outside?

The reasons I am asking:
1. I want to know whether it would make sense to run one of these with a CO2 generator. If it is exhausting your growroom air, then this would be a bad idea cause you're just wasting money venting out all that CO2!
2. Odor control, if it's venting out your growroom air then there's air being vented that isn't going through your carbon filter, another BAD THING!

Anyone know?

Thanks!

QuentinQuark said:

Hi folks,

I have a questions about those portable A/C units, the ones that have two ducts (intake & exhaust) to the window.

What I'm wondering is, do they exhaust the air from inside your room? Or do they only exhaust the air that they bring in from outside?

The reasons I am asking:
1. I want to know whether it would make sense to run one of these with a CO2 generator. If it is exhausting your growroom air, then this would be a bad idea cause you're just wasting money venting out all that CO2!
2. Odor control, if it's venting out your growroom air then there's air being vented that isn't going through your carbon filter, another BAD THING!

Anyone know?

Thanks!

Click to expand...

The 'dual hose' portable AC units are designed to "use" outside air to generate the flow needed to produce the cold air. They snatch hot/cold air from outside and exhaust the same air directly back out. (So no new air from outside is being drawn in nor is no new air being replaced in your grow room).
So basically, the 'dual hose' AC Units re-circulate the air inside the room; a 'perpetual' cooling setup. This method
is the best way to conserve/retain CO2 and keep the room cool.

Fresh air once per hour is recommended, and probably at least once per day is needed for healthy growth.

The Portable AC Units that do not have drip pans, that "exhaust excess moisture out the exhaust hose", will remove a small amount of air inside your room. But i'm not sure how much yet. I haven't tried it yet.

I would still need fresh air that often??

How do people set up completely sealed rooms then?

Even the dual hose a/c's with drip pans aren't 100% percent sealed. The only 100% sealed a/c units are the split a/c units. They are comprised of two different parts. The compressor and must sit outside of the growroom. \

Check this link: http://www.icmag.com/ic/showthread.php?t=89009

Also, here is a C02 calculator, it will give you some important information as far as venting , read everything.

http://www.hydroponics.net/learn/co2_calculator.asp

I am setting up a one hose portable a/c in the room my tents are in. The temp in the tents is fine most days, but we also happen to use this room to smoke in. It gets upwards of 90 degrees when we've been in there smoking. The two challenges we've run into thus far is smell and odor being exhausted outside. We've swapped out the basic intake filter (intake on this model is inside) with a carbon filter and I'm making a replacement exhaust panel out of plywood with foam sandwiched between to hopefully lower the amount of sound that escapes. Also going to switch out the plastic hose for some insulated ducting. Hopefully this will let us smoke and talk freely in the room without our neighbors knowing. If this doesn't work, I'll likely try making a thicker carbon filter and fitting it to the exhaust.

QuentinQuark said:

I would still need fresh air that often??

How do people set up completely sealed rooms then?

Click to expand...

I'm really unsure how often to ventilate; but I know it's recommended, but i'm not sure how often is needed for healthy growth. Maybe someone else could recommend?

hwy420 said:

Fresh air once per hour is recommended, and probably at least once per day is needed for healthy growth.

Click to expand...

I disagree. Plants only need fresh air to get rid of oxygen and replenish co2. If you are supplementing properly with co2, you do not need to vent unless you have a heat issue.

A completely sealed room isn't a room that is never ventilated. It is a room that is sealed for long enough to allow plants to use implemented CO2. Once the CO2 is used by the plants, fresh air is sucked into the room, ready to be implemented with new CO2. This process keeps the air oxygenated. I should mention, however, that cannabis only uses CO2 during the light cycle. Achieving ventilation every few hours, but keeping the room sealed during CO2 supplementation can indeed be tricky. One way is to buy a a fan that has a back draft door. It sucks new air in the room, but once it's turned off during the CO2 cycle it won't allow air to escape back out. Look under the ventilation category at htgsupply.com to find one of these once the site is back up, they are moving to a different warehouse right now.

Cannabis releases oxygen mindphuck, but the also use it via respiration. Having the plant use the oxygen it produced would be possible, but I don't think it would be optimal. I also wonder if cannabis has access to the nitrogen in the air.

DenseBuds said:

I am setting up a one hose portable a/c in the room my tents are in. The temp in the tents is fine most days, but we also happen to use this room to smoke in. It gets upwards of 90 degrees when we've been in there smoking. The two challenges we've run into thus far is smell and odor being exhausted outside. We've swapped out the basic intake filter (intake on this model is inside) with a carbon filter and I'm making a replacement exhaust panel out of plywood with foam sandwiched between to hopefully lower the amount of sound that escapes. Also going to switch out the plastic hose for some insulated ducting. Hopefully this will let us smoke and talk freely in the room without our neighbors knowing. If this doesn't work, I'll likely try making a thicker carbon filter and fitting it to the exhaust.

Click to expand...

The one hose (the cheaper model) pulls air from the room.

If you have a separate exhaust blower, I would try to tie it there. A potable A/C blower doesn't have enough umph behind it to exhaust through a filter.

I have one of those single hose ac units. I have a large cylindrical carbon filter which sucks air from my room and through my light then exhausts it.. Think it would be possible to somehow attach the output hose of the sac unit to the outside of the carbon filter? thereby giving me a cold room but still odor filtered?

Green Cross said:

The one hose (the cheaper model) pulls air from the room.

If you have a separate exhaust blower, I would try to tie it there. A potable A/C blower doesn't have enough umph behind it to exhaust through a filter.

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Thanks. That does concern me a bit. I tried to find the cfm rating on the a/c but all I could find was "airflow". It said it was 212 and the exhaust air FEELS about the same as my exhaust on my tent which goes through a carbon filter. If I can't filter the a/c somehow, I will remove it completely and hook up the same fan/filter setup I have in my tents to exhaust out the window. I figure that would fix the smell for sure and likely suck cool air in under the door from the rest of the house.

onehandedroller said:

I have one of those single hose ac units. I have a large cylindrical carbon filter which sucks air from my room and through my light then exhausts it.. Think it would be possible to somehow attach the output hose of the sac unit to the outside of the carbon filter? thereby giving me a cold room but still odor filtered?

Click to expand...

I guess it would depend on what the intake on the ac looks like. Mine is a large rectangle screen. I guess I could duct tape something to it, but it doesn't sound very solid to me.

Higher Education said:

Cannabis releases oxygen mindphuck, but the also use it via respiration. Having the plant use the oxygen it produced would be possible, but I don't think it would be optimal. I also wonder if cannabis has access to the nitrogen in the air.

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There's plenty of o2 made by the plants to use for respiration. The reason air gets 'stale' is the decrease in co2. This was one of the great combined discoveries by Joseph Priestly and Jan Ingen-housz. O2 is needed in the rootzone and like you said during respiration during dark hours. Since co2 isn't needed at night, it is fine to vent the room but during the day when photosynthesis is dominant, you don't need fresh air, just new co2 and then it will produce abundant o2, enough to get it through the dark period, no problems.[/QUOTE]

Hello.

I have a portable a/c unit and other then the power issue when also using multiple hps lighting systems, it works great. Mine only has one hose and i have it venting into the ceiling where it dissipates through attic vents. It takes the air out of the room and the exhaust air is very hot and smells very strong. It also has a drip bucket that needs to be emptied every few days. Hope that helps.

Dave

floydsmith716 said:

Hello.

I have a portable a/c unit and other then the power issue when also using multiple hps lighting systems, it works great. Mine only has one hose and i have it venting into the ceiling where it dissipates through attic vents. It takes the air out of the room and the exhaust air is very hot and smells very strong. It also has a drip bucket that needs to be emptied every few days. Hope that helps.

Dave

Click to expand...

Does yours have a replaceable filter? Curious to see how well those thin CarboStat filters work. I've got mine installed, but nothing smelly right now to test (nothing to smoke and the carbon filters in my tents keep my larger room odor free).

mindphuk said:

There's plenty of o2 made by the plants to use for respiration. The reason air gets 'stale' is the decrease in co2. This was one of the great combined discoveries by Joseph Priestly and Jan Ingen-housz. O2 is needed in the rootzone and like you said during respiration during dark hours. Since co2 isn't needed at night, it is fine to vent the room but during the day when photosynthesis is dominant, you don't need fresh air, just new co2 and then it will produce abundant o2, enough to get it through the dark period, no problems.

Click to expand...

[/QUOTE]

Ok, makes sense, I was unaware that respiration only took place at night. Thanks!

Ok, makes sense, I was unaware that respiration only took place at night. Thanks!

Click to expand...

I didn't mean to mislead you, I probably could have phrased that better. Respiration occurs all of the time but it is only at night when the photosynthesis shuts down that the plants need to rely on residual o2 since it isn't making anymore. IOW the o2 levels during the day shouldn't be an issue since photosynthesis makes it. Remember, plants are responsible for creating the o2 in the early earth's atmosphere and continues to this day. If they utilized as much or more o2 than they produced, we wouldn't have it in excess.

Trust me, it is possible to grow healthy, vibrant plants in a completely sealed room as long as co2 is supplemented.

Ok, well that's what I needed to know mindphuk.

BUT, I checked out the icmag thread, and all I got from it are that somebody says that the dual hose ACs don't pull air out of the room, and somebody else says they do

I'm sure that they're not supposed to, but can anyone tell me of their experiences with CO2 and dual-hose ACs, do they suck the air out of the room?

Hey quentin.

I got a sealed, dual hose a/c unit, (I think it's like 9,000 btu's), a CO2 burner, 1000watts, and I tried my damn best to get the room sealed as best as possible.

The way I can primarily gauge how well I did, is by considering how often the burner has to kick on, to bring the room up from 1000 to 1500 ppms CO2,

and i'm amazed how rarely it has to burn, I think like on average, over every fifteen minutes... I think thats pretty good. I can go almost a month on a tank of propane in my 6 by 8 by 7 room.

About the a/c... I like it, because it also dehumidifies... my room is often at 30% rh. I love it.

*But yes, the unit does put a slight negative pressure on the room, and the hot warm air it puts out into a crawl space, some comes back into the house and pools at a stairwell, and smells of the CO2 and other byproducts from the burner, so yeah, a little, but negligible amount of pull out of the room. Most air stays recirculated. I'm happy with the equilibrium. enough truly "fresh" air i suppose, which is not much i hope...

I wanna find some of that iodine purple gas stuff that you can use to find leaks to see everywhere i'm leaking beyond just the door frame...