Fresh air intake needed?

Smtty025

Member
I'm a newbie. I built a sealed room in my attic. I have a 6inch exhaust fan with carbon filter. And I also installed a 4inch round duct with can-filter to add fresh air into the room. I'm adding a co2 soon. How's my setup?
 

JoeBlow5823

Well-Known Member
I'm a newbie. I built a sealed room in my attic. I have a 6inch exhaust fan with carbon filter. And I also installed a 4inch round duct with can-filter to add fresh air into the room. I'm adding a co2 soon. How's my setup?
"Adding fresh air into a room" and "running a sealed room with co2" are not something you can do at the same time. Its either sealed or its not. If you have air intake/exhaust, all your co2 is just wasted money.
 

JoeBlow5823

Well-Known Member
So what should I do not run the exhaust and run the fresh air intake?
If you push fresh air into the room, the co2 rich air thats already in the room has to go somewhere. You cant add air to a room without air exhausting somewhere...... A sealed room is just that... SEALED. No air in. No air out. If you arent running sealed, co2 is a waste.
 

TintEastwood

Well-Known Member
I'm a newbie. I built a sealed room in my attic. I have a 6inch exhaust fan with carbon filter. And I also installed a 4inch round duct with can-filter to add fresh air into the room. I'm adding a co2 soon. How's my setup?
Co2 or not. Sealed rooms usually have venting. When and how to use it will vary.


What are you using for AC? Control temp/rh?
 

JoeBlow5823

Well-Known Member
Co2 or not. Sealed rooms usually have venting. When and how to use it will vary.


What are you using for AC? Control temp/rh?
Well your right there... My point was more that it doesnt sound like he is anywhere near ready for the co2 game yet. Just figuring out how to keep temps right in an attic will be struggle enough.
 

TintEastwood

Well-Known Member
Well your right there... My point was more that it doesnt sound like he is anywhere near ready for the co2 game yet. Just figuring out how to keep temps right in an attic will be struggle enough.
We agree. Indeed could be challenges in the attic.
No reason to complicate things with Co2 for most new growers.
 

Keesje

Well-Known Member
Co2 or not. Sealed rooms usually have venting. When and how to use it will vary.
I wouldn't call it 'venting'.
Even in a sealed room there are always tiny holes that air will slip through.
And with growing cannabis where it is not legal, most growers will need some kind of under pressure, to prevent smell to escape.
But if you don't care about the smell, and you do have AC to control the heat and some kind of dehumidifying to control the RH, you would need no ventilation at all.
Also ethylene should be no problem as long as your CO2 burners work well and you don't leave rotting leaves
 

TintEastwood

Well-Known Member
I wouldn't call it 'venting'.
Even in a sealed room there are always tiny holes that air will slip through.
And with growing cannabis where it is not legal, most growers will need some kind of under pressure, to prevent smell to escape.
But if you don't care about the smell, and you do have AC to control the heat and some kind of dehumidifying to control the RH, you would need no ventilation at all.
Also ethylene should be no problem as long as your CO2 burners work well and you don't leave rotting leaves
Venting refers to using intake and/or exhaust fans.

My statement holds true.
 

Keesje

Well-Known Member
Perhaps I did not write it well. Apologies for that.

But you would not need venting at all.
I know people do it, but there is no reason for it.
The reason people do it, are mostly because of controlling the smell. So that has nothing to do with the CO2.
If you have other ways to control the smell (with Ozone for example) and you can control heat and RV, there is no need for intake and/or exhaust fans.

Or do I misunderstand you?
Then please explain to me why you think it is needed?
 

TintEastwood

Well-Known Member
Perhaps I did not write it well. Apologies for that.

But you would not need venting at all.
I know people do it, but there is no reason for it.
The reason people do it, are mostly because of controlling the smell. So that has nothing to do with the CO2.
If you have other ways to control the smell (with Ozone for example) and you can control heat and RV, there is no need for intake and/or exhaust fans.

Or do I misunderstand you?
Then please explain to me why you think it is needed?
Respect. I think we agree venting is not required.

Do we agree that sealed rooms usually have fans and ducting in place? That was my main point.
 

Keesje

Well-Known Member
I know most rooms have it.

I also know that sometimes people do it because they don't understand enough of what the plants need.

People think that plants need 'fresh air' even when they are adding CO2.
And in itself it is true, but it is not true at the same time.
The gasses plants need are CO2 and O2.
CO2 you add.
O2 is in the room. Even if your room would be totally 100% sealed (which is never the case. Perhaps in a laboratory it is) there is already plenty of O2 for weeks.
Growers like us, who build rooms with tiny gaps, and who visit the room through a door, will make sure that there is always enough O2.
Way more then the plants will ever absorb.
 

jondamon

Well-Known Member
Respect. I think we agree venting is not required.

Do we agree that sealed rooms usually have fans and ducting in place? That was my main point.
Sealed rooms that utilise DEHUEY, HUEY, Co2, AC usually have a recirculating filter and fan set up in the room itself to recirculate smelly air within the sealed environment.

some people choose to vent and exhaust during dark hours but usually that’s from a seperate filter and exhaust setup that are damper controlled.
 

jondamon

Well-Known Member
I know most rooms have it.

I also know that sometimes people do it because they don't understand enough of what the plants need.

People think that plants need 'fresh air' even when they are adding CO2.
And in itself it is true, but it is not true at the same time.
The gasses plants need are CO2 and O2.
CO2 you add.
O2 is in the room. Even if your room would be totally 100% sealed (which is never the case. Perhaps in a laboratory it is) there is already plenty of O2 for weeks.
Growers like us, who build rooms with tiny gaps, and who visit the room through a door, will make sure that there is always enough O2.
Way more then the plants will ever absorb.
O2 is produce by the plants!

remember that simple plant biology lesson where we are taught that plants use Co2 and give back o2.
 

Keesje

Well-Known Member
O2 is produce by the plants!
That is irrelevant for growers.
A plant will never produce so much CO2 during the night, that it will raise the level of CO2 during the day.
And it will also never produce as much O2 that it is enough for the roots.

That would be a perpetual motion and that is also impossible in biology.

Sealed rooms that utilise DEHUEY, HUEY, Co2, AC usually have a recirculating filter and fan set up in the room itself to recirculate smelly air within the sealed environment.
Perhaps where you live.
But I can assure you that most growers who grow where it is illegal, will not do it this way.
You can never filter out all the smell with a recirculating filter within the room.
So there is still a chance that smell will escape. For that it is better to have a really small filter and exhaust fan. And thus create under pressure.
For sure you will suck out some CO2, but then you just add more.
 
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jondamon

Well-Known Member
That is irrelevant for growers.
A plant will never produce so much CO2 during the night, that it will raise the level of CO2 during the day.
And it will also never produce as much O2 that it is enough for the roots.

That would be a perpetual motion and that is also impossible in biology.



Perhaps where you live.
But I can assure you that most growers who grow where it is illegal, will not do it this way.
You can never filter out all the smell with a recirculating filter within the room.
So there is still a chance that smell will escape. For that it is better to have a really small filter and exhaust fan. And thus create under pressure.
For sure you will suck out some CO2, but then you just add more.
And FYI plant processes reverse at night where more oxygen is used and more Co2 is created.


Anyone who creates a sealed room and uses ventilation for a few times a day to remove any additional offgasing has created a Hybrid room and not sealed environment.

I agree any new grower should not look to incorporate a “sealed” style environment as it will be counter intuitive to creating a zero smell environment.

I’m from the U.K. and it’s illegal and I run with a ventilation system.

it’s only where offgasing is an issue with building materials such as plastics, paints, varnishes etc that growers have found issues utilising sealed rooms.

granted even the most well sealed room still isn’t 100% sealed but I can tell you from experience that if a sealed room is setup correctly you would not be able to smell any of the grow unless the door was opened.
 

Keesje

Well-Known Member
And FYI plant processes reverse at night where more oxygen is used and more Co2 is created.
I think all schoolkids know this.
So what is your point?
It is irrelevant for us growers when it comes to having a sealed room yer or no. But thanks for the info!

The rest of your post I don't really understand, but that's ok.

Just this: Creating a room sealed in such a way that no smell will escape, is almost impossible.
If you think it is... go for it.
But I think otherwise and most growers with sealed rooms where I live agree with me.
 

Keesje

Well-Known Member
That sounds kind of stupid from someone growing in DWC.
If you run a decent airstone then there is plenty of O2 in the water for plant roots.
But if you stick your whole head in that same water for 10 minutes you're dead.

And if you don't use an airstone in DWC your plants will not do well.
Even though there is more then enough O2 in the room where a man could survive easily.
 
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