Help a newbie better understand ventilation and temperature/humidity control.

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BigB 420

Well-Known Member
Hi guys. First time poster. I've been reading for quite a while but I haven't needed to post before now.

So I have 1 grow under my belt. 4 clones grown outdoors. I had a lot of fun, but now I'd like to plan an indoor setup. I love the idea of having more control, possibly being able to try hydroponics, and not having to worry about the rain/fog/bugs/rippers/unexpected guests, etc. DWC and UCDWC are the most appealing to me right now. I would build a system myself if I go that route.

I have a 9.5' x 10' (ceiling is 7' and slopes to 6' on the other) storage room with a cement floor behind my laundry room that I think will work well once I add a nice door that locks, insulation, and some more electrical connections. I'll probably divide the room into 3 area's, a small veg area with florescent lights for clones and a few mothers, a larger (4-6 plants to start) veg/flower area with a ballast (probably a single air cooled 600 watt) that can run a MH or HPS so that I can veg for a few weeks before flowering if needed, and a small storage area that may also double as a drying room. Though I've also considered using the flower room as a drying room by shutting off the lights and leaving the ventilation on.

The room has 3 exterior walls that can easily be used for ventilation. My thought was to install a passive intake low on one wall (with a basic filter to keep out bugs and dirt), and a carbon filter + exhaust fan high on the opposite wall. (I'm prop 215 legal but I'd rather not have to explain the smell to guests or invite rippers) I figured I could hide each vent behind one or two of those hardware store household ventilation grates that are used on basements and attics.

What I'm having a hard time wrapping my head around is how to properly control both temperature and humidity in this room. I plan to run the lights at night to keep the room warmer during cold winter nights and cooler during hot summer days. The weather here is pretty mild but we do get some cold nights (below freezing a few times a year), plenty of rain, and some 90-100 degree days in the summer. With the room air being exchanged on a regular basis (I see some people keep their exhaust fan on 24/7, others run it on a timer or a thermostat) how do I control the room's internal temperature?

If my intake is pulling in fresh outside air that might be hot, freezing cold, and/or damp. How do I keep the room in the correct range? Are fans and moving air enough to keep most rooms stable?

I totally grasp the idea of using a basic thermostat/humidity controller to fire up the ventilation fans whenever it's too hot or too humid, but what if my intake air is 30f? What if it's 100f? what if it's a warm rainy day and the outside humidity is 90%? In those situations it almost seems like fresh air might do more harm than good.

I know that heaters, air conditioners, and dehumidifiers are an option but even then with the room air being regularly replaced won't I be blowing all of my newly temperature adjusted dehumidified air right out of the room and potentially replacing it with more hot/cold/damp air? This seems like it would be a huge waste of electricity.

So, am I over-thinking this? or am I going to need to seal the room and run a bunch of heating/cooling equipment and C02?

I know many people hook their intake up to a living space to get indoor air from their house that might be more mild, but this room doesn't share a wall with any living area's. It shares a wall with an un-insulated laundry room, and an open car port.

Thanks!
 
ASMALLVOICE

ASMALLVOICE

Well-Known Member
Hiya M8,
You are going to have your hands full if you want to bring in "raw" outside air as the only means of "intake" for the space. The swings in both temperature and humidity are going to beat you down fairly quick without a means to "pretreat" the air before introducing it to the grow space. I would try to find a way to do a little "pretreat" in the laundry room space you mentioned, like a heater and/or a dehumidifier and try to keep the grow temps where you need them to be. Having "raw" darn near frozen air coming into a toasty grow space is going to open the proverbial "Pandora"s Box" if you will and more than likey be detrimental to the crop. Hollar if you have any more questions.

Good Luck and Steady Temps :P

Asmallvoice
 
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Michelangelo00

Active Member
I agree raw air is a bad idea. I have enough trouble with temp/ humidity with air from my living area. If money isn't a big deal, seal it and get co2. You will have more control and less worry once it is operational. I don't use them but I know some like the large controlers such as: http://www.amazon.com/gp/aw/d/B003A78CFU
 
M

Michelangelo00

Active Member
Another option would be to build a closet that keeps your ac heater and humidity controlers to pretreat the air. With a room that size, I wouldn't try to grow anything until it is stable.
 
B

BigB 420

Well-Known Member
Ok thanks guys. So "raw" air is a bad idea. So much of the stuff I've read just say to pull in "fresh" air that I assumed most people were using outside air. I'll have to reconsider my intake.

I like the idea of pre-treating the air but heating and cooling equipment gets expensive pretty fast. If I'm doing that I might be better off sealing her up and using CO2. I'd have nearly all the equipment at that point.

Maybe if I build the grow areas as two large "boxes" within the room, the remainder of the room could have the intake and function as a pretreat area. Basically like a tent inside a room. Could the exhaust be on a timer so that there would be time for air outside of the grow area too heat/cool/dehumidify?

I'm just worried that doing that would use a lot of electricity. It would be like running your A/C or heater with the windows open.
 
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Michelangelo00

Active Member
If you are looking for perfect conditions, get co2. If not, get a cheap window unit/ heater and roll with it. What are your goals? Do you want good weed or better than you could ever buy?
 
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BigB 420

Well-Known Member
I doubt I could ever grow anything "better" than I could buy. The dispensaries nearby already have pretty good quality available and I have some friends who are always happy to hook me and my wife up in exchange for a donation or trim work. They have a non profit collective.

My outdoor grow yealded several ounces that's at least on par with what I can buy.

I guess my goal would be to grow good quality medacine for my wife and I, as well as my sister in law. To hopefully save some money in the process and I also consider growing to be a fun interesting hobby. I like the science and the challenge of trying to grow the best stuff I can. I don't have a need for any large quantities but if I can manage to grow some extra I could donate it to some local dispensaries or other patients to help cover my costs.

I'm looking at my space this morning and it looks like I could use inside air for my intake but I would have to run about 30' of intake duct along the ceiling of my laundry room and cut holes in two walls. That would be pretty hard to hide. My wife wants everything hidden so her religous family members can still come to visit.
 
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crailtapper

Member
i bought a cheapy furnace filter and built a box around it with slits in the front and a hole in the back and draw my intake into my room to avoid dusts and pests. if it's your laundry room you obviously have random bacteria coming in from where ever those clothes have been. i found the box easy to build and it gives me peace of mind knowing you're getting cleaner air to your plants. depending on what furnace filter you choose, you may need a small inline duct fan to help move air through the filter. definitely finish your build and get everything running before you start growing. my first grow is almost into flower and i just finished my room today. its been a bitch rushing to get the right temps and air flow while dodging my plants the whole time working in the heat of the lighting.

can you explain how you want to hide your grow? 100%? i.e. your mother in law does some laundry and doesnt have a clue? or do you mean hiding just the vent holes attaching into other rooms? im a carpenter so let me know and i will try to help you out with better ideas. just dont ask me plant questions yet lol
 
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BigB 420

Well-Known Member
The problem with venting in from the laundry room is it's not sealer or insulated so it get hot in the summer and cold in the winter, It could be insulated and closed off if needed but it still doesn't have any heating or cooling like the rest of the house does.

As far as hiding the grow, yes 100% would be ideal. The room itself will be behind a locked door to the "storage" room. The reason we will tell people it's locked is that it contains my gun collection. Any other vents, wires, water hoses, etc. just need to be out of sight or appear "normal". Basically it needs to be as hidden as possible from the outside and appear as a "normal" locked storage area. If there is any fan noise I will tell people that I purchased a dehumidifier to keep my guns from getting rusty.
 
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crailtapper

Member
oh i understand now. i thought you were growing in laundry room and were going to make a separate room in there. should be pretty easy to hide then. just put some thick weather stripping around your door for light and air leaks. the bottom of the door will be the tricky part. quickest/easiest fix i can think of is to have some sort of bull nosed raised flooring at the bottom. in other words a piece of wood that covers that half inch gap at the bottom of your door. just match the flooring so i doesnt stick out. then just weather strip the inside of that. does this storage room share any walls with insulated rooms? if it doesnt you might be in for some work to make it 100% hidden. if it does a simple hole in the wall to the regulated room with a vent cover should be good enough for your air intake as long as you dont get any light leak. a few bends in your venting can help that. exhaust should be pretty simple. hole on the outside of your house and vent to it using insulted venting and an insulted vent cover. how many sockets if any are in your storage room? be sure to leave room for storing stuff like nutes, soil, water bottles and other various equipment. also consider where you will be drawing your water from. the temp/ph/chlorine/chloramine factors. since i dont like running around my house with water supplies and what not i keep a reservoir in my room that has been aired out for chlorine and is temp controlled and constantly bubbled. just something to consider to help you stay hidden and stealthy all the while your plants are getting the best of the best. hope this helps!
 
B

BigB 420

Well-Known Member
The room has 3 exterior walls. The 4th wall is shared with the laundry room. That's why the cold/hot/humid fresh air is a problem. My plan was to divide the inside of the storage room into 3 rooms. Flower/veg, clones and mothers, and a drying/ equipment storage area. Water can come from the laundry room sink. It has a hose feeding the washer that I can split with a Y pipe behind the washer and run through the wall into the room. I'm on a well so I'm pretty sure my water is good but I haven't tested it yet. My outdoor plants did fine on it though.

Electrical will have to be installed. Right now the room only has a shop light on the ceiling. No outlets. But the fuse box is only about 20 feet away in the car port so having a few outlets installed shouldn't be too expensive.

The challenge is still intake air. Outdoor "raw" air isn't going to work and wife said no to a sealed room due to equipment cost.

If I can't solve the intake air issue. I may be stuck growing outdoors for a while.
 
I

imchucky666

Well-Known Member
BigB 420 said:
Hi guys. First time poster. I've been reading for quite a while but I haven't needed to post before now.

So I have 1 grow under my belt. 4 clones grown outdoors. I had a lot of fun, but now I'd like to plan an indoor setup. I love the idea of having more control, possibly being able to try hydroponics, and not having to worry about the rain/fog/bugs/rippers/unexpected guests, etc. DWC and UCDWC are the most appealing to me right now. I would build a system myself if I go that route.

I have a 9.5' x 10' (ceiling is 7' and slopes to 6' on the other) storage room with a cement floor behind my laundry room that I think will work well once I add a nice door that locks, insulation, and some more electrical connections. I'll probably divide the room into 3 area's, a small veg area with florescent lights for clones and a few mothers, a larger (4-6 plants to start) veg/flower area with a ballast (probably a single air cooled 600 watt) that can run a MH or HPS so that I can veg for a few weeks before flowering if needed, and a small storage area that may also double as a drying room. Though I've also considered using the flower room as a drying room by shutting off the lights and leaving the ventilation on.

The room has 3 exterior walls that can easily be used for ventilation. My thought was to install a passive intake low on one wall (with a basic filter to keep out bugs and dirt), and a carbon filter + exhaust fan high on the opposite wall. (I'm prop 215 legal but I'd rather not have to explain the smell to guests or invite rippers) I figured I could hide each vent behind one or two of those hardware store household ventilation grates that are used on basements and attics.

What I'm having a hard time wrapping my head around is how to properly control both temperature and humidity in this room. I plan to run the lights at night to keep the room warmer during cold winter nights and cooler during hot summer days. The weather here is pretty mild but we do get some cold nights (below freezing a few times a year), plenty of rain, and some 90-100 degree days in the summer. With the room air being exchanged on a regular basis (I see some people keep their exhaust fan on 24/7, others run it on a timer or a thermostat) how do I control the room's internal temperature?

If my intake is pulling in fresh outside air that might be hot, freezing cold, and/or damp. How do I keep the room in the correct range? Are fans and moving air enough to keep most rooms stable?

I totally grasp the idea of using a basic thermostat/humidity controller to fire up the ventilation fans whenever it's too hot or too humid, but what if my intake air is 30f? What if it's 100f? what if it's a warm rainy day and the outside humidity is 90%? In those situations it almost seems like fresh air might do more harm than good.

I know that heaters, air conditioners, and dehumidifiers are an option but even then with the room air being regularly replaced won't I be blowing all of my newly temperature adjusted dehumidified air right out of the room and potentially replacing it with more hot/cold/damp air? This seems like it would be a huge waste of electricity.

So, am I over-thinking this? or am I going to need to seal the room and run a bunch of heating/cooling equipment and C02?

I know many people hook their intake up to a living space to get indoor air from their house that might be more mild, but this room doesn't share a wall with any living area's. It shares a wall with an un-insulated laundry room, and an open car port.

Thanks!
Click to expand...
Sounds well thought out!
If you are in your basement, you can do what I did for my smoking area downstairs, and cut a couple holes for registers (vents) in your heater ducts.
This works well, as you can open/ close them, but it will work more efficiently if you also add a return (obviously you will need to filter it as well for the smell so as not to circulate it throughout the house).
Then too, if you insulate well, your temps shouldn't fluctuate TOO terribly bad if you use light on at night like you mentioned. most of your summer heat will affect the upstairs more than the basement.
2 sides here are basically underground, being on a hill, but insulating 2 walls with the pink roll stuff really helped over the summer, and with winter here or close, we'll see how much it helps.
 
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imchucky666

Well-Known Member
BigB 420 said:
The room has 3 exterior walls. The 4th wall is shared with the laundry room. That's why the cold/hot/humid fresh air is a problem. My plan was to divide the inside of the storage room into 3 rooms. Flower/veg, clones and mothers, and a drying/ equipment storage area. Water can come from the laundry room sink. It has a hose feeding the washer that I can split with a Y pipe behind the washer and run through the wall into the room. I'm on a well so I'm pretty sure my water is good but I haven't tested it yet. My outdoor plants did fine on it though.

Electrical will have to be installed. Right now the room only has a shop light on the ceiling. No outlets. But the fuse box is only about 20 feet away in the car port so having a few outlets installed shouldn't be too expensive.

The challenge is still intake air. Outdoor "raw" air isn't going to work and wife said no to a sealed room due to equipment cost.

If I can't solve the intake air issue. I may be stuck growing outdoors for a while.
Click to expand...
If you can pull inside air, and exhaust to the outside, you will have help there controlling temps, as it won't be pulling cold or excessively hot air.
 
M

Michelangelo00

Active Member
Haha. I really don't think people read threads before they post. I was just checking on your progress. I have an idea. Perhaps you could insulate the laundry room and put an ac/heater combo in there. Then pull air from there and exhaust out. If your lights are air cooled to the great outdoors, it should work. Although you would need a nice sized intake and exhaust fan. Your wife should be happy with a climate controlled laundry room and you will be happy with the grow room.
 
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BigB 420

Well-Known Member
That's about where I'm at right now. I was talking to a friend today who grows on a large scale in a dedicated building. He suggested using tents and using the space in the laundry room and storage room around the tents for intake air. Then the laundry room and storage room could be insulated and have a small passive intake and some climate control. A space heater in the winter and an A/C in the summer. Both on thermostats. Maybe set the heater for like 65ish and the A/C for 75ish.

I would probably still install a door to close off the storage room but maybe allow air to pass between it and the laundry room passively. With weather stripping, insulation, and covering any windows I could hopefully keep the area relatively temprature stable. With the cement floor it stays pretty cool in there when the windows are covered. I used this area as a drying room for my outdoor plants and it stayed pretty cool even when it was hot out.

My friend also has a small room controller that he said I could use. He doesn't use it anymore.

He thinks I should only veg indoors and then throw all the plants outside next summer to flower but that's just because in his eyes a small grow is too much work for a small yield.

I'm not sure on the tents like he suggested just because they're kinda expensive but I think using them or building rooms with wood frames and plastic will have basically the same results.
 
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Michelangelo00

Active Member
My tomatoes are housed in a 4x4 made from 1/2" foam panels ( lowes for 9-11$, 4x8)and 2x4s. It took a couple hours to build, it cost a great deal less, it's sealed, insulated, and the frame can support anything I need. I recommend building one any day. Check you tube out if you need a start point.
 
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BigB 420

Well-Known Member
Cool thanks. I'll check that out. Building does seem cheaper than tents.

I had a lightbulb go off this morning and I think I have an idea that will work for keeping the area warm on cold winter nights, without having to run a heater so often.

Normally with air cooled lights I would use an intake, exhaust, and a basic inline fan to pull cool air across the lights and then blow it back outside. My idea is to use a couple of electronic duct dampers. Such as these: http://www.discount-hydro.com/electric-duct-dampers/

I could use one that's "normally open" at the end of the lamps exaust, and another that's "normally closed" right before it on a basic Y pipe. Both could be plugged into a thermostat or room controller so that when the air temperature around my growing box/tent falls below a certain point the "normally open" duct would close, and the "normally closed" duct would open. This would automatically pump the warm air from the light back into the area around the box/tent and use it for heat until the temperature rose above my set point and then it would begin pumping the air outside again. The great thing is that while the exaust from the lamp is warm, it should still be as rich in CO2 as outside air.

I think if the lamp makes enough heat, I would only need a space heater during those odd times that it got really cold during lights out, and if I run my lights at night that shouldn't be very often.

Now the hardest part is going to be to the wife approve all of the equipment. I'll start by talking about all the delicious Grandaddy purple I could grow. She loves that stuff.
 
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Michelangelo00

Active Member
Thats a great idea. I never thought of doing that. Hmm I might have to rework my ventilation now. Wow though... 100 bucks each? I think you could just put your exhaust fan on the thermostat.
 
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BigB 420

Well-Known Member
Yeah that mich be an option and I imagine this thing could be found cheaper somewhere. It's just basic heating cooling equipment that hydro shops probably mark up. You could probably even build one.

Turning the lights exhaust fan on/off might work just as well. Can grow lamps overheat? I'm guessing they do fine without exhaust. They sell lights without air cooling after all.
 
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