I have an idea which is quite simple that many people probably thought about, for my bud room i'll be running 6,000 watts and was wondering if it would be safe to bring fresh cold air from outside into the room to cool it down. I live in michigan and winter is here temperatures right now are around 50's and below during the day. I was thinking of hooking an inline fan or two to a thermostat to regulate the fan when it reaches a certain temperature. I know that bringing outside air could also bring in pest and mold but are they a problem in the winter? Obviously I would need an a/c in the summer but if I can get at least one harvest without having to buy my mini split ($3000) i'll be happy. Let me know what you guys think. . . .oh yeah, if I end up doing it this way im not going to run co2 until i get the mini split and completely seal off my room, because some holes will have to be made for the ducting since the windows are located outside of the bud room.
Alternative a/c for the winter!!!?
- Thread starter Blaze23
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HanginIron
Active Member
4000 watts. I draw outside air through my hoods and back outside. exhaust fan with filter sucks outside air through 2 passive intakes. I don't run ac in the winter, just a dehumidifier.
Alright cool, Im glad others are doing/have done the same things before, what kind of filter do you have? Is there any way you can take a picture of your intakes?
HanginIron
Active Member
I used a 6" hurricane fan with a cheap filter for my exhaust, works great with 3 lights. Runs full time when I kick on the 4th, need to upgrade. The intakes simply have a 1" thick piece of foam behind the board. 2x6" dropping to about an inch above the floor. Yeah, the carpet is gone, the pic is from when I was first setting up the room.
The 8" runs to my hoods and has its own fan on a speed control.For filters I just use 1 inch thick foam. It also helps to spray the intake filter with the bug killer of your choice once in a while as I believe there is no filter made that will keep spider mites out 
Make sure that the air in and air out is balanced, as a negative air pressure can cause havoc with your plants. Not sure what a positive pressure will do.
I made that mistake and had hell trying to figure out what was wrong with my plants. I finally figured out that because of the negative air pressure my growing enviroment was like trying to grow at 7 or 8 thousand ft. above sea level. Not good.
Make sure that the air in and air out is balanced, as a negative air pressure can cause havoc with your plants. Not sure what a positive pressure will do.
I made that mistake and had hell trying to figure out what was wrong with my plants. I finally figured out that because of the negative air pressure my growing enviroment was like trying to grow at 7 or 8 thousand ft. above sea level. Not good.
So is negative pressure when you put too much air into the room and not enough exhaust? or is it the opposite?For filters I just use 1 inch thick foam. It also helps to spray the intake filter with the bug killer of your choice once in a while as I believe there is no filter made that will keep spider mites out
Make sure that the air in and air out is balanced, as a negative air pressure can cause havoc with your plants. Not sure what a positive pressure will do.
I made that mistake and had hell trying to figure out what was wrong with my plants. I finally figured out that because of the negative air pressure my growing enviroment was like trying to grow at 7 or 8 thousand ft. above sea level. Not good.
negative pressure is when the air going out is less than the air comming in. I had 3 exhaust fans blowing out and a small hole that allowed air in. The intake hole was to small to effectively replace the air that was drawn out. It created low air pressure. Like a vacumm cleaner. Positive air pressure is the other way around, like blowing up a baloon. the air in the baloon has a positive air pressure in relation to the ambiant air pressure.
HanginIron
Active Member
What kind of problems does neg pressure create? Curious because when my exhaust is running I have a hard time closing the door to my room and it isn't even sealed.For filters I just use 1 inch thick foam. It also helps to spray the intake filter with the bug killer of your choice once in a while as I believe there is no filter made that will keep spider mites out
Make sure that the air in and air out is balanced, as a negative air pressure can cause havoc with your plants. Not sure what a positive pressure will do.
I made that mistake and had hell trying to figure out what was wrong with my plants. I finally figured out that because of the negative air pressure my growing enviroment was like trying to grow at 7 or 8 thousand ft. above sea level. Not good.
ASMALLVOICE
Well-Known Member
Hiya Folks,
Negative pressure occurs when the exhaust is greater than the intake. Positive pressure is when intake is greater than the exhaust.
Problems with too much in either direction will have negative consequences on the area served.
Positive - applys force outward to everything it contacts - tents swelling, smells escaping, doors not closing properly, increased fan noise and fan lifespan shortened.
Negative - pulls inward on everything it contacts - collapses tents, doors not opening properly, pulls in contaminated air from any and all leaks in the area served. Excessive fan noise and fan lifespan shortened.
You can do a flow check with a piece of paper cut out to just about 60% the size and shape of the intake hole. Have your venting system running and grasping the piece of paper on it's edge between your thumb and forefinger. Hold the piece of paper over the intake hole and if it sucks it into the intake hole to the point it is horizontal, you are showing excessive negative pressure. If the paper blows out, then you are showing a positive pressure.
When you get the ratio right, the paper should only be pulled in very slightly( lightly negative ), almost wanting to just hang there. This will stop a grow tent from collapsing or swelling up, depending on your situation.
Hope this helps.
Peace and Great Grows
Asmallvoice
Sir.Ganga
New Member
With 12 lights running I have 2 6" intakes and 1 10" exhaust. From Oct. to march or april. Saves big dollars not running 3 a/c units. If you exhaust at a rate greater then your intakes you create neg pressure and the smell remains in you room not your house.
Carbon filters do work (kinda) but for getting rid of smell I use a ozone generator(air tiger 3), it goes inline of your exhaust and eliminates smell 110%
Good Luck
Carbon filters do work (kinda) but for getting rid of smell I use a ozone generator(air tiger 3), it goes inline of your exhaust and eliminates smell 110%
Good Luck
HanginIron
Active Member
My question was about Randm's comment
I wanted to know what kind of havoc neg pressure creates for the plants?
ASMALLVOICE
Well-Known Member
The effect on the plants from the actual negative pressure you can create wil not hurt them directly other than possibly starve them for CO2, but collapsing a tent or losing a fan will have implications, such as heat or humidity build up, plant breakage, among others..
Peace
Asmallvoice
Look at how plants grow at a higher altitude, as opposed to a lower altitude. Its all about air pressure and available oxygen. At sea level there is plenty of both o2 and co2 so the plants are happy. The higher you go the thinner the air is ( like negative pressure in a room ) and the plants are more stunted. That is what happened to my plants, it was as if I had taken them to a higher altitude and tried to grow on a mountain top. By having an imbalance in air in / air out with the air out being greater than the air in you are effectively re-creating a higher altitude type of enviroment. My plants where stunted, slow to finish, or just stalled out and suceptible to other health problems.
A very small imbalance is fine, in fact a slight, very slight, negative pressure is preferable as mentioned in the above post for controlling smell, among other things.
Just something to think about.
A very small imbalance is fine, in fact a slight, very slight, negative pressure is preferable as mentioned in the above post for controlling smell, among other things.
Just something to think about.
noober doober
Active Member
OP, just keep in mind that if you are only using outside air to cool you are going to lose a lot of control. I live in the north east and though our winters are plenty cold, it's tough to rely on it. Some nights I would find it way too cold, then if we had a string of warmer weather temps could breach 90f. I've personally given up on using winter air to cool my tent, it's just too variable. However, as far as bugs, I just pulled through a regular screen on the window and never had a problem with bugs...