Using A/C without exhausting Co2 ?

Hi RIU... So my question is in the title... If you have a sealed room with a 600w bulb, how could you run A/C to that room without exhausting the added co2 when the a/c exhausts it's heat ??

Is there anyway to do this? Or do you basically have to cool the whole room the grow box is in to cool the outside ambient temperature ? I have used co2 before but pretty much wasted it all by not sealing the room and exhausting it through my carbon filter and cool tubes...

I know to cool the lights without exhausting co2 is simple, just duct the lights from outside the box, then exhaust outside the box... But the A/C is what's got me stumped. doesnt seem like there's a really efficient way to do it.

Many ways to do this. First what kinda ac you got a windows unit or a portable unit. If its a portable unit just use a homemade adapter that surrounds the cold air out put and a flex duct. Put the capture around the cold air output area and run the flex duct to the grow box or tent or what ever. If its a window unit do the same except the unit is in a window. With co2 also remember you still have to do full air exchanges couple times a day so old air out fresh air in co2 back on. I use dampers and timers to set air exchanges and co2 refills. Also with co2 you need temps bit higher around 80 to 85 F to make use of the co2.

Purchase a split air conditioner...easiest fix, just costly JAS

portable ac. has hoses hooks to the exhaust. shoot the heat out the furnish vent. or chimney or a window, all honestly . if you need to run a ac unit. grabs about 1000 watts run 12 hours a day. that's about 120 dollars every harvest, so you know. it might be best to vent the room with an exhaust fan

FilthyFletch said:

Many ways to do this. First what kinda ac you got a windows unit or a portable unit. If its a portable unit just use a homemade adapter that surrounds the cold air out put and a flex duct. Put the capture around the cold air output area and run the flex duct to the grow box or tent or what ever. If its a window unit do the same except the unit is in a window. With co2 also remember you still have to do full air exchanges couple times a day so old air out fresh air in co2 back on. I use dampers and timers to set air exchanges and co2 refills. Also with co2 you need temps bit higher around 80 to 85 F to make use of the co2.

Click to expand...

It will be a portable unit, most likely dual hose... But I'm sorry, I guess I don't understand what you wrote.... So I set up the unit as normal. One hose/duct pulling air from the outside to the a/c... Then the heat exhaust hose/duct vent to outside the room... But then on the front side of the a/c unit (where the cold air actually comes out of) I build a little sealed box ? So technically the sealed box is getting cooled but I vent that cool air to the grow box? Is that right?

If that's right, wouldn't the a/c unit be really inefficient as it's thermostat is going to be monitoring that little sealed box instead of the grow box?

kinddiesel said:

portable ac. has hoses hooks to the exhaust. shoot the heat out the furnish vent. or chimney or a window, all honestly . if you need to run a ac unit. grabs about 1000 watts run 12 hours a day. that's about 120 dollars every harvest, so you know. it might be best to vent the room with an exhaust fan

Click to expand...

Yea that's obviously the best and cheapest way to do it, if applicable. But in my situation the grow box is in the garage where there is no insulation and the temperature fluctuates with the outside temp... So heat won't be an issue as of now since winter is almost here, But in the summertime it would probably get around 90 f + with a light. Maybe more. So an a/c would be a must have. My grow room isn't that big anyways, so I only need like a 5000 btu unit which is about 600-800 watts. Still a lot but it is necessary.

Another option that helps a lot with heat is to run at night. I did a complete flip of my light schedule mid flower and experienced no negative results and my room dropped a good 10 degrees

My portable ac units are setup with 1 vent hose which goes out a window or tapped into an exhaust of some sort. Now on the front of all mine and those I have seen you have the intake fan down low behind the gratting where this takes air in. Now above that is usually the area the cold air comes out. This is where you make the cover with a vent attachment and hook the vent house to it. I am assuming you have a small grow box if I read right not big enough to put the entire unit in the grow box? Your thermostat wont be real accurate like this you are correct. What you need to do is see is how long it takes the box to cool when the ac is running and then use a simple cycle timer from like walmart and set the unit to turn on in intervals such as ok if I run it 10 minutes it cools the box and that lasts an hour before temps up again or if its flower use only during lights on. You ll have to do some tinkering to figure out your needs. maybe you only need it to kick on during the days hottest hours so set the timer for those times. Just set your temp on the ac to what you want to cool the box to during that time....Small boxes are difficult but this can make it happen. You can also just tap into your home vent duct and run a line to the box and then the box will be the temp of your home

your light is vented right ? if so an exhaust fan is best for a small personal grow. usually only large grows, use ac, during extream hot days, and other days its vented,

Only a split-system will do what you want. Uses refrigerant so no air escapes that way. All portable and window units will exhaust the air and odor. Split system acts like a fridge for that room. High BTU and high CFM can cool large rooms with lots of heat.

The issue with rillchilldudes idea is he is looking to cool the box not the garage in full and a split unit is way to big for a small grow box and the cost would just be stupid when much easier cheaper things can be done. I would assume the box has a scrubber on it and since a portable unit will not be taking air from the box no smell is pushed out the box. The air exchange is still done via the boxes intake and output fans and vents which the exhaust will be going through the carbon scrubber or whatever he uses.

rickymac21 said:

If that's right, wouldn't the a/c unit be really inefficient as it's thermostat is going to be monitoring that little sealed box instead of the grow box?

Click to expand...

It will be even more inefficient when there is no return on the already cooled air. The only way you're gonna run co2 and cool the room without exhausting room air and do it efficiently is gonna be a split ac system or water cooling.

FilthyFletch said:

My portable ac units are setup with 1 vent hose which goes out a window or tapped into an exhaust of some sort. Now on the front of all mine and those I have seen you have the intake fan down low behind the gratting where this takes air in. Now above that is usually the area the cold air comes out. This is where you make the cover with a vent attachment and hook the vent house to it. I am assuming you have a small grow box if I read right not big enough to put the entire unit in the grow box? Your thermostat wont be real accurate like this you are correct. What you need to do is see is how long it takes the box to cool when the ac is running and then use a simple cycle timer from like walmart and set the unit to turn on in intervals such as ok if I run it 10 minutes it cools the box and that lasts an hour before temps up again or if its flower use only during lights on. You ll have to do some tinkering to figure out your needs. maybe you only need it to kick on during the days hottest hours so set the timer for those times. Just set your temp on the ac to what you want to cool the box to during that time....Small boxes are difficult but this can make it happen. You can also just tap into your home vent duct and run a line to the box and then the box will be the temp of your home

Click to expand...

This sounds simple enough... This is actually what I had in mind but I didn't realize the heat extraction point was different from the cool air output point. I figured once the unit was done blowing cool air it would suck hot air through the same vent. But now that I think about it that makes no sense.. I'm sure after a week or so I could easily have it dialed in so I don't have to touch it again.

Thanks for the input and quick responses, love this forum.... like I said though, winter is about here so I won't even have to worry about all this for another 6 months or so... Just planning ahead.

Side question if anyone is bored enough to read and answer : I have a 400w but I want to upgrade to 600 or 1000... If I went vertical, with either of those lights, how would you set the room up ?
I.E... 12 plants surrounding the light vegged to say 12" to finnish at 24-28" ?
24 plants surrounding light vegged to 6-8"
Or maybe even 40 plants surrounding light with little to no veg ?
Also thought about a simple half stadium (tiers only go up on two sides, not all 4 sides) and doing a s.o.g. with enough plants to fill the space...

I've done horizontal grows forever now and I'm just not getting the yields I want (mostly my fault with room conditions). But I'm ready to step up my game and see what I can pull.

There's a picture of what I came up with the help of FilthyFletch.... Sorry if it's hard to understand but I just sketched it up real quick... But basically on the left you can see the a/c unit is outside of the grow box with a ducting vent that would be sealed off so all cold air directly vented into the grow room... Then the lower portion of the a/c unit where the heat is extracted is not connected to the grow box in any way so no cooled air, co2, or odor is exhausted.... Then my vertical light is vented with ducting that runs from outside the room on both ends so no co2 or cooled air is pulled from the grow box...

My fault, I can't ever get pictures to come up large on this forum ...