Okay I finally took some pics of my grow cab. Im having major heat problems, the temps in the middle of the cab halfway to the lights get to about 95F but the temps at the floor stay in the high 70's to low 80's. What can I do to fix this heat issue without spending too much money? I have a 95cfm pc fan on the filter for exhaust and 3 2'' intake holes. I can stack another of the same fans to the exhaust to make it stronger but wanted to make sure it would fix it before i do. I also have a small pc fan inside blowing at the bulbs which are (2) 70watters, and the inside dimensions are 30'' x 11'' x 25''. Any suggestions?
small cab...hot!
- Thread starter The_Joker
- Start date
freeride high
Member
you need more airflow in the cab and more vent power.
what grouchy said. kiss says 2x passive intake. if your fan is 5" diameter, you need two 5" holes for intake. If your intake holes aren't the same size as the exhaust fan, you still need 2x total intake. Trust me, it'll help.
How many threads and how many times do we have go through this?
The answer remains the same:
You're continuing to choke your cab. A 120 mm fan takes TWO (2) 120 mm intakes. If you want to stick to 2 inch intakes, you'll want EIGHT (8) of them.
Starting a new thread with a different title isn't going to change the answer.
The answer remains the same:
You're continuing to choke your cab. A 120 mm fan takes TWO (2) 120 mm intakes. If you want to stick to 2 inch intakes, you'll want EIGHT (8) of them.
Starting a new thread with a different title isn't going to change the answer.
grouchy
Active member
But how would we know to point him to the search button if he didn't start a new thread?
yes i have already inquired about this same problem but the reason i asked again is because i have changed the intake since then and am still having problems, also i figured this thread would e better suited for this section than the other. sorry for any inconvenience i have caused you FreezerBoy
While you may have "changed the intake" you knew before you tested and certainly before you posted that you hadn't changed nearly enough. I know this because I've seen the answers in your previous thread.
The easy fix: punch two holes in the bottom of the cab with a 4" hole saw. The hard fix: punch 8 holes in the bottom of the cab with a 2" hole saw. Either way, intake area is double the exhaust area.
The easy fix: punch two holes in the bottom of the cab with a 4" hole saw. The hard fix: punch 8 holes in the bottom of the cab with a 2" hole saw. Either way, intake area is double the exhaust area.
Outportgrower
Member
Think that people really do need to read a little. The answer is out there for those that take a few moments to look. As FB stated, take your exhaust and double the size you have to use as your intake. Pretty simple math really.
1" fan = 2" intake
2" fan = 4" intake
3" fan = 6" intake
and on, and on, and on. Now how you go about creating that double intake size is really up to you. But I would not try cutting a single two foot hole for a 12" exhaust mind you. Look at four six inch holes to come out with double your 12" exhaust size.
Good lord I remember seeing a complete thread here on ventilation. Bet if ya did a search on Ventilation you would find it
.
1" fan = 2" intake
2" fan = 4" intake
3" fan = 6" intake
and on, and on, and on. Now how you go about creating that double intake size is really up to you. But I would not try cutting a single two foot hole for a 12" exhaust mind you. Look at four six inch holes to come out with double your 12" exhaust size.
Good lord I remember seeing a complete thread here on ventilation. Bet if ya did a search on Ventilation you would find it
.
Outportgrower
Member
You really want to be pulling cool air in from the bottom. Heat will go up and be pulled out by your fan. You want to have the cooler air coming in at the bottom so it can rise collecting the built up heat on it's way out and keep your temps in check.
Think that people really do need to read a little. The answer is out there for those that take a few moments to look. As FB stated, take your exhaust and double the size you have to use as your intake. Pretty simple math really.
1" fan = 2" intake
2" fan = 4" intake
3" fan = 6" intake
and on, and on, and on. Now how you go about creating that double intake size is really up to you. But I would not try cutting a single two foot hole for a 12" exhaust mind you. Look at four six inch holes to come out with double your 12" exhaust size.
Good lord I remember seeing a complete thread here on ventilation. Bet if ya did a search on Ventilation you would find it
.
Good post but your math is a little off. The area of a circle is equal to pi x radius squared. The area of a:
2" circle = 2.14 sq.inches
3" circle = 4.8 sq. inches
4" circle = 8.56 sq. inches
5" circle = 13.4 sq. inches
So, you would need 4 x 2" intakes to be double a 2" exhaust, and so on.
Edit: That math is wrong too. See Freezerboy's post a little further down for the correct math.
PC
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Hey Freezer,
Just wondering how you easily lightproof two 4 inch holes? What is your method? It is easier and less work yes, but lightproofing them can be harder if you do not have the space.
Joker,
First off, might not be able to cool those down with that fan hooked up to a carbon filter. And if you have any chance, you need way more intake. You are wasting your time asking questions until you cut enough intake. Why on earth would you want to cut vent holes near the top, when you have plenty of room at the bottom? If you cut holes at the top, your fan will suck that air first..instead of cool air from the bottom. Even with 8 two inch holes, if your fan is not powerful enough, it wont cool your cab. If you cannot afford a new fan, you could revamp your set up and put your lights in a cool tube. Also, where are you venting your hot air? If it is in the same room as your cab, that will raise your cab temps.
Not being rude, but you seem like you should do some reading before you go any further. Use the search function, look at similar cabs, do some research before you start your plants. Dont start until you are ready, otherwise you will be asking basic questions your whole grow. People will respect you more if you show you are helping yourself learn. You have gotten all the RIGHT answers from alot of people in 2 threads, so do what you like with the info, but dont waste anymore of your or our time until you use the advice. Good luck!
Just wondering how you easily lightproof two 4 inch holes? What is your method? It is easier and less work yes, but lightproofing them can be harder if you do not have the space.
Joker,
First off, might not be able to cool those down with that fan hooked up to a carbon filter. And if you have any chance, you need way more intake. You are wasting your time asking questions until you cut enough intake. Why on earth would you want to cut vent holes near the top, when you have plenty of room at the bottom? If you cut holes at the top, your fan will suck that air first..instead of cool air from the bottom. Even with 8 two inch holes, if your fan is not powerful enough, it wont cool your cab. If you cannot afford a new fan, you could revamp your set up and put your lights in a cool tube. Also, where are you venting your hot air? If it is in the same room as your cab, that will raise your cab temps.
Not being rude, but you seem like you should do some reading before you go any further. Use the search function, look at similar cabs, do some research before you start your plants. Dont start until you are ready, otherwise you will be asking basic questions your whole grow. People will respect you more if you show you are helping yourself learn. You have gotten all the RIGHT answers from alot of people in 2 threads, so do what you like with the info, but dont waste anymore of your or our time until you use the advice. Good luck!
u need more exhaust and def more active intake, and having your lights at the top like u do makes little sense to me, why not hang them vertically, get twice the floor space out of the equation plus allow the hot temps to rise up away from your canopy also, i still dont understand why people arent running vertical setups when they have the space, all the decent yeilds off 150 ive seen are with vertical grows, im taking 5 ounce pulls not 2-3 ounces like most seem to get. id double decker that cab with only partial shelves on the sides to support plants and go vert, put a fan on the bottom blowing straight up to the exhaust and add a few strong intakes, those 70s are just to week to have much penetrating power and youll be raising your girls with (books, lunchboxes etc) any way u can just to reach em. just my two cents and perspective on being a space miser, one of the most wasted resources in indoor growing today-
Um, can you simply leave the door open during lights on ?
That would eliminate the need to go punching out more holes.
That would eliminate the need to go punching out more holes.
Outportgrower
Member
http://www.icmag.com/ic/showthread.php?t=112862
Ventilation 101 Everything you need to know and a little bit more.
Ventilation 101 Everything you need to know and a little bit more.
Outportgrower
Member
No steely eyed Missile Men we
No steely eyed Missile Men we
Everybody slips up once in a while so don't think I'm excluding myself but, MAN was Buzz Aldrin lucky we weren't doing the math that fateful day...
Those numbers quadruple (4X) the exhaust.
To double intake: Two intakes both equal in size to the exhaust or, A=π(1.415r)²
Example:
Area of a 3 inch diameter hole is 7.065". Double the Area is 14.13"
r=1.5
1.5x1.415=2.1225
2.1225²=4.505
4.505π=14.14 square inches
To double the Area of a 3" hole with a single intake would require an intake of 4.25 in diameter.
Nice try but, your math is a little off
2" circle = 3.14 sq.inches
3" circle = 7.065 sq. inches
4" circle = 12.56 sq. inches
5" circle = 19.625 sq. inches
6" circle = 28.26 sq. inches
Four 2" holes (A=12.56) quadruples a single 2" hole (A=3.14) Two 2" holes (A=6.28) is double the area of a single 2" hole (A=3.14).
No steely eyed Missile Men we
Everybody slips up once in a while so don't think I'm excluding myself but, MAN was Buzz Aldrin lucky we weren't doing the math that fateful day...
Those numbers quadruple (4X) the exhaust.
To double intake: Two intakes both equal in size to the exhaust or, A=π(1.415r)²
Example:
Area of a 3 inch diameter hole is 7.065". Double the Area is 14.13"
r=1.5
1.5x1.415=2.1225
2.1225²=4.505
4.505π=14.14 square inches
To double the Area of a 3" hole with a single intake would require an intake of 4.25 in diameter.
Nice try but, your math is a little off
2" circle = 3.14 sq.inches
3" circle = 7.065 sq. inches
4" circle = 12.56 sq. inches
5" circle = 19.625 sq. inches
6" circle = 28.26 sq. inches
Four 2" holes (A=12.56) quadruples a single 2" hole (A=3.14) Two 2" holes (A=6.28) is double the area of a single 2" hole (A=3.14).
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