[ChomeFactory]

Weird. I wonder why it’s higher in the other room.

I like the vent idea. Put it lower on the wall. Co2 is heavy.

[mike6011]

Inside house vs. outside house.

[jmystro]

All I have is questions. Plants need stable CO2 levels because their morphology depends on it. Are plants currently consuming any CO2 from lung room? What is generating CO2 in these rooms and what is using CO2? Where are the plants? The ppm levels will not maintain 450 in lung room or 800 in another room if plants are pulling CO2 from either. Venting the high ppm air into the lung room will obviously raise the ppm but for how long? What’s creating high levels of CO2 in the ‘other room’ that wouldn’t be instantly depleted?

[mike6011]

Yes. I understand all of that. When I add the natural drafted air it will raise the PPM. That was the original question. Is it worth the trouble to cut the hole. The best part of the design is it should work as long as the pressure in the house is higher than the shed. Maybe I end up with 750PPM. That is still an improvement. Am I going to notice an improvement? I also intend to add some additional CO2 gas to the tent when the lights are off as well. I will inject it into the steam from a humidifier. I understand CO2 is heavier than ambient air.

[jmystro]

Cut holes if you feel you need to. Do what ya gotta do to win.

[green-giggles]

Why is the next room higher CO2?

Are YOU in the next room?

[flowerpower]

My lung room is in my bedroom. I get over 750 PPM of CO2 overnight while my lights are on and I’m asleep. Seems to be doing fine. I produce my own CO2 LOL

[ChomeFactory]

I hang out in my lung room 70% of the day. It’s enough to elevate the co2. I’m helping my plants in more ways than expected.

[Killdozer]

I also just hang out in the lung room.light a candle and listen to dgc, smoke a blunt. plenty of CO2. although I wonder if my girls know I’m smoking their family and they are next in line.. my CO2 is in the 3000 range never gets more than 6000.. week 5 bloom.

• This reply was modified 2 weeks ago by  Killdozer.

[mike6011]

6000? Are you sure about that? I think over 2000 will kill you if you breathe it. I’m using an A/C Infinity CO2 controller to measure.

[miljeff420]

You’d be surprised how much the concentration of CO2 can rise with just people in a smaller space. I was growing mushrooms for a while and really tracked it. And no 2000 parts per million of CO2 won’t kill you, not even close.

[Killdozer]

she’s little lower today maybe my exhale bag is dieing but yeah I hang out in here and smoke blunts I’m guessing is why.

[Killdozer]

I was actually wondering about that how much is to much? she is one crazy hungry girl that’s for sure I feed her the aggressive feed schedule 3 times a week. not to highjack the thread…

• This reply was modified 2 weeks ago by  Killdozer.

[porc]

I sleep with plants around them most the time but still add no mercury c02 tablets in the water mix res feed I hand feed by the way so yh c02 at all times more the better but steadily as u can loose it quickly from air exchange n overload dumping pesonal expedience

[mike6011]

Thanks for the quick replies. I should have given more detail. My lung room is an air conditioned shed. It runs 450PPM. It is located right next to my house and lines up with a closet that I intended to cut a 4″ hole out and access the 900PPM air from inside my house. I thought I could use a small computer fan and move some air. I’m not sure of the static pressure differences but I would think my house static pressure is higher than the shed and would have a small amount of natural air flow.

[dBuds]

You’re on the right track here. 450 ppm isn’t bad, but if the room next door is cruising at 800–900 ppm, that’s basically a CO₂ buffet going to waste. Before cutting holes like you’re planning a prison break, start with airflow. CO₂ is heavy and lazy—it sinks low and doesn’t move unless you make it. Get a fan low on the wall pushing air from the high-CO₂ room into the lung room. Make sure it circulates, not just swirls around like a confused fart.

And here’s the overlooked kicker: if you spend time in that 800+ ppm room, you are the CO₂ generator. Humans are little CO₂ factories—every breath you take is pumping that number up. So, if you want to help your plants without doing much else? Just move your CO₂-emitting self into the lung room more often. It’s low-tech, but it works.

For an even easier win, toss a couple of self-activating mushroom-style CO₂ bags into the room. No electricity, no venting, just passive boost. They’ll keep things elevated and steady, especially when the tent is sealed and not much fresh air is coming in.

So yeah, venting can help—but airflow and a little CO₂ backup bag combo might be your best return for the least effort. Plants will love you, and you won’t have to hide from your landlord with a spackling knife later.

[dBuds]

Also, I saw you mentioned running an A/C unit for your lung room—does it exhaust its heat outside the shed? If so, that’s likely contributing to your CO₂ drop. Those systems can slowly purge CO₂ over time as they cycle, especially if they’re not sealed tight.

Honestly, just toss a CO₂ bag into the lung room and thank me later—it’s low effort and gives you a steady passive boost without all the ductwork drama.

But that said, like most folks will tell you: CO₂ is a luxury add-on, not the foundation. You’ll get way more mileage dialing in your grow first—light intensity, VPD, feed schedule, airflow—before chasing extra CO₂. Unless you’re pushing above 800 PPFD at the canopy, you’re not really even in the range where your plants need elevated CO₂. They just won’t uptake it efficiently without that light intensity driving photosynthesis.

So yeah, get everything else locked in first—then if you want to supercharge things, CO₂ becomes the cherry on top.

[dBuds]

Now that I understand your lung room is actually a shed detached from the house, I’d strongly recommend against cutting any holes to bridge the two. That’s just asking for headaches—humidity imbalance, pests, heat bleed, and a permanent “what was I thinking?” moment in the drywall.

Honestly, just grab a $30 CO₂ bag every 6–10 months and call it a day. It’s simple, low-maintenance, and way more efficient than trying to Frankenstein two buildings together for a couple hundred ppm.

There are smarter, more effective ways to reach your goal—you just gotta zoom out a bit. Stop thinking one-dimensional and start thinking like a grower who builds systems that work with your space, not against it. Efficiency beats effort when it’s done right.