So I have been doing a lot of reading and research on my new grow starting in February and need some help with ventilation. I am going to run two 600w HPS sealed hoods with 6in vent holes, my plan is to seal the box the best as possible and have the exhaust fan passively by negative pressure bring in fresh air through one way vents at the bottom of the box. I want to have the air exhaust through a carbon filter then through my hoods then out of the box into the vent my gas heater exhausts to, will i need a one way duct valve to make sure nothing from my heater enters my box?. I think I am going to run a 300cfm fan too is that enough? does this all sound okay, just looking for some advice
4 x 8 x8 grow box ventilation
- Thread starter mlitz
- Start date
fir3dragon
Well-Known Member
I wouldn't exhaust where your heater is.. Find another spot.
also, I would run a minimum 6 inch fan for the, 2 600w hid lamps. Honestly I would go with a 8 inch, and just dial it down cause a 6 inch at full is gonna sound like a jet..
also, I would run a minimum 6 inch fan for the, 2 600w hid lamps. Honestly I would go with a 8 inch, and just dial it down cause a 6 inch at full is gonna sound like a jet..
tkowitha123
Well-Known Member
as long as you have more air pressure from your lights you should be fine other than it may force to vent towards your heater, if it were me I would use 2 seperate lines one for my heater and 1 for my lights. You may need a back pressure valve to stop your exhaust from venting into your heater box. You might look into a bathroom vent fan with an heatlamp for your intake and then just vent like normal with your exhaust fan. I like the bathroom vent fan because you can put different wattage lightbulbs into the fixture till you find a perfect wattage to control your room temps. not to mention you can wire a bathroom vent fan so you can just flip a switch to turn your heat on/off and leave the fan running contently. Don't know if you've thought about a bathroom exhast fan or not but it works great for me and I got one off ebay for like 60$, it serves as an intake fan and a heater for me...2 birds with one cheaper stone,lol
AimAim
Well-Known Member
The basic setup sounds OK except I would not want to be putting a pressurized air exhaust column into my water heater venting. I'd be more worried about that, then what the water heater exhaust might do to your grow area.
There's some guys on here that know their shit about venting and ducting but I am not one of them, they'll show up eventually and give you a better answer.
I'm just not sure what you are proposing is safe.
LonelySmoker
Member
Do not duct your exhaust into your heater, that is not safe.
You will prevent carbon monoxide from escaping the pipe from the heater because there won't be enough room in the line for all of the air to escape.Too much air volume. Every duct/pipe has a capacity and the gas heater exhaust isn't rated for that heavy of a load.
What you should do is vent directly into the attic, above insulation level. What kind of climate do you live in? Generally, the volume of air in an attic is an adequate buffer to prevent mold from moisture and heat build-up.
Also, a 300CFM fan attached to a carbon filter, (2) 600W lights, and ducting will not even come close to keeping that thing cool IME. Go back to the drawing board here.
To me, the ideal setup for you would be to cut a whole in your ceiling to fit the ducting through (keep the circular piece for later repair when you decide to move), mount your fan in the attic that is sucking the air through your equipment, and do a short but straight duct run to ensure the exhaust isn't blowing directly onto anything (like insulation).
For example:
Carbon filter>>>>>>600W Hood>>>>>>>600W Hood>>>>>>>Fan>>>>>>>>Attic
Minimize the bends in your ducting as much as possible, and go with an 8 inch fan with 8 inch flanged hoods. I recommend the Radiant 8; fantastic reflectors.
What are the ambient temperatures in the room where this box will be located? That may change some of my analysis a little, but for the most part I think it will stay the same.
The more equipment (fan, ballast, etc) you can keep on the outside of the box, the better. Get a small shelf to put on the side of the box for your ballasts to sit on along with other essentials.
When considering your carbon filter, you will want to go with a lower rating than your fan, not a lot, but definitely lower. That is because your fan will not be attached directly to the filter, which will alter the CFM rating. You have the choice of ceiling mounting the filter or setting it on a cinder block or two about plant level. I prefer the latter because it is easier to deal with moving it.
One other consideration: intake. Passive intake will likely not produce enough air flow to keep a negative pressure on the box. Buy a blower fan to force air into the box on the opposite side of the carbon filter. Also have your oscillator blowing towards the filter. This will create the most efficient path for the air to travel.
If anyone wants to call me out, feel free.
I have done a setup like this before and it worked flawlessly with temps 4 inches under the reflector of 77 degrees, ambient temps of 72. If you provide me with your climate information/temperature information I can help you further evaluate your setup.
Hope that helps you some. Happy Growing!
You will prevent carbon monoxide from escaping the pipe from the heater because there won't be enough room in the line for all of the air to escape.Too much air volume. Every duct/pipe has a capacity and the gas heater exhaust isn't rated for that heavy of a load.
What you should do is vent directly into the attic, above insulation level. What kind of climate do you live in? Generally, the volume of air in an attic is an adequate buffer to prevent mold from moisture and heat build-up.
Also, a 300CFM fan attached to a carbon filter, (2) 600W lights, and ducting will not even come close to keeping that thing cool IME. Go back to the drawing board here.
To me, the ideal setup for you would be to cut a whole in your ceiling to fit the ducting through (keep the circular piece for later repair when you decide to move), mount your fan in the attic that is sucking the air through your equipment, and do a short but straight duct run to ensure the exhaust isn't blowing directly onto anything (like insulation).
For example:
Carbon filter>>>>>>600W Hood>>>>>>>600W Hood>>>>>>>Fan>>>>>>>>Attic
Minimize the bends in your ducting as much as possible, and go with an 8 inch fan with 8 inch flanged hoods. I recommend the Radiant 8; fantastic reflectors.
What are the ambient temperatures in the room where this box will be located? That may change some of my analysis a little, but for the most part I think it will stay the same.
The more equipment (fan, ballast, etc) you can keep on the outside of the box, the better. Get a small shelf to put on the side of the box for your ballasts to sit on along with other essentials.
When considering your carbon filter, you will want to go with a lower rating than your fan, not a lot, but definitely lower. That is because your fan will not be attached directly to the filter, which will alter the CFM rating. You have the choice of ceiling mounting the filter or setting it on a cinder block or two about plant level. I prefer the latter because it is easier to deal with moving it.
One other consideration: intake. Passive intake will likely not produce enough air flow to keep a negative pressure on the box. Buy a blower fan to force air into the box on the opposite side of the carbon filter. Also have your oscillator blowing towards the filter. This will create the most efficient path for the air to travel.
If anyone wants to call me out, feel free.
I have done a setup like this before and it worked flawlessly with temps 4 inches under the reflector of 77 degrees, ambient temps of 72. If you provide me with your climate information/temperature information I can help you further evaluate your setup.
Hope that helps you some. Happy Growing!
Okay so I am putting the box in my garage, the garage is below two bedrooms so no attic unfortunately. any other ideas? here is two picture of the garage, the first one is where the box is going to go the second is the rest of the garage.
I live in the PNW (Portland, OR area)
I have no problem going to an 8in hood
I see what you mean by blower fan... do you have a cfm suggestion?
Yes ballast and fans will be out of the box
Anything else you need to know?
I live in the PNW (Portland, OR area)
I have no problem going to an 8in hood
I see what you mean by blower fan... do you have a cfm suggestion?
Yes ballast and fans will be out of the box
Anything else you need to know?
Purpsdro420
Well-Known Member
I just built a similar setup same size and lights. I went with a 6" inline for the lights and a 8" inline fan and filter for exhuast. temps are perfect at 73f. But my ambient temps are 60f
LonelySmoker
Member
Tricky layout!
Before I begin to develop a solution, would it be at all possible to re-locate the operation to a spare bedroom? If you are able to, you will end up spending a lot less time "putting out fires". You will be much happier and have a much more positive experience.
Keep in mind that come peak flower time (June assuming you get going early February), the ambient temps in the garage are going to be high, thus the fresh air going into your box will also be high. Unless you ran A/C of course, but that also has to be vented.
Let me know about the relocation and then we will dive into this and hammer out a plan.
Before I begin to develop a solution, would it be at all possible to re-locate the operation to a spare bedroom? If you are able to, you will end up spending a lot less time "putting out fires". You will be much happier and have a much more positive experience.
Keep in mind that come peak flower time (June assuming you get going early February), the ambient temps in the garage are going to be high, thus the fresh air going into your box will also be high. Unless you ran A/C of course, but that also has to be vented.
Let me know about the relocation and then we will dive into this and hammer out a plan.
AimAim
Well-Known Member
See? I knew it ! LonelySmoker offering up great advice.
3 year member and 70ish posts are the guys you want to listen to. Not like me where I tend to blather.
I understand the need for it, but trying to do this on somewhat of a budget.
LonelySmoker
Member
LOL thanks AimAim.
I usually don't post unless I feel very compelled, which is usually only in the case of a truly unique circumstance where I have experience.
Most of the post you see here on RIU could easily be answered by looking through the forum and having a true desire to learn, so I don't bother responding to lazy asses. However, I love to help people that are in a bind and at least made an effort to find a solution on their own. As far as general discussion/opinion goes, not much of a talker since it usually gets me in trouble lol. Hence the name
Peace brother, and happy growing!
LonelySmoker
Member
Problem not solved. Where are you going to vent the exhaust? After all, that is what we are trying to figure out.
You should never exhaust a portable A/C with longer than a 5-6 foot hose or the condensing unit will burn out prematurely and create enough condensation to fill a 5 gallon bucket during one light cycle. That is if you take the drain plug off the unit and tilt it to allow the drip. If you don't, the internal reservoir will fill quickly and the unit will cut off. That won't do anyone who has to go to work any good.
The issue here is the logistics of the setup, not the equipment.
LonelySmoker
Member
Mlitz, thank you for getting back.
What exactly is your budget, and what are your goals? Let's look at this from a holistic approach. You can buy a 4x8 tent for $210 on Amazon.
Sorry I keep coming up with more questions, but the more I know, the better I can help. Don't worry, we will get this figured out. Just want to give you the best possible solution I can.
What exactly is your budget, and what are your goals? Let's look at this from a holistic approach. You can buy a 4x8 tent for $210 on Amazon.
Sorry I keep coming up with more questions, but the more I know, the better I can help. Don't worry, we will get this figured out. Just want to give you the best possible solution I can.
okay it is an okay budget, we are splitting things 3 ways I guess maybe $2000 total. I want be able to grow 4-6 plants, hopeful yield of 1lb per harvest.
oh the second thing I worry about is electrical in the master, the circuit breaker box is in the garage so less worry for that.
oh the second thing I worry about is electrical in the master, the circuit breaker box is in the garage so less worry for that.
LonelySmoker
Member
I will do a little pondering with all of these considerations in mind and get back to you within the next day or two.
You're going to need roughly 16-18 amps of capacity, which is a concern of mine since it is unlikely you have a free 30 amp breaker wired in the panel. Do you have the mechanical aptitude to do some wiring?
Also, still have to do the math on the air flow.
This particular setup is perhaps one of the most challenging I have encountered given the specs you are wanting. Frankly, the cost might exceed your budget to make it feasible with quality equipment.
It may end up being a bit more pragmatic to change the approach altogether, as in, going with one 600W for flower in the master bedroom (for environmental control) and making you a nice veg room in the garage. Flower is your bread and butter and you want the most ideal conditions when in that growth phase, whereas plants in veg are a little more forgiving and can take more abuse.
You can get great results under lower heat T5's for veg in the garage, but when you bring on the heat of an HID lamp it will eat your lunch during summer. Nothing wrong with scaling down a little and getting a solid perpetual going that is turnkey and needs very little maintenance rather than "going big" and end up fighting the whole way.
You're going to need roughly 16-18 amps of capacity, which is a concern of mine since it is unlikely you have a free 30 amp breaker wired in the panel. Do you have the mechanical aptitude to do some wiring?
Also, still have to do the math on the air flow.
This particular setup is perhaps one of the most challenging I have encountered given the specs you are wanting. Frankly, the cost might exceed your budget to make it feasible with quality equipment.
It may end up being a bit more pragmatic to change the approach altogether, as in, going with one 600W for flower in the master bedroom (for environmental control) and making you a nice veg room in the garage. Flower is your bread and butter and you want the most ideal conditions when in that growth phase, whereas plants in veg are a little more forgiving and can take more abuse.
You can get great results under lower heat T5's for veg in the garage, but when you bring on the heat of an HID lamp it will eat your lunch during summer. Nothing wrong with scaling down a little and getting a solid perpetual going that is turnkey and needs very little maintenance rather than "going big" and end up fighting the whole way.
blackforest
Well-Known Member
I have a similar setup and exhaust into the basement. Keeps it warm, no smell. NO reason to exhaust through flume.
