about fresh air....

im in my 3rd grow and improving evry time but still cant nail this fresh air thing, i have a 435 cfm fan bringing in air full time, theres another 435 pulling air out full time, prob is its hott as hell here and the ac i have in the window never turns off, i was told to always have fresh air coming in but before it got hot my last crop about killed me with the light bill, now its hott and im fighting it. if i was too put the air on a timer would that hurt?? 30 on 30 off?? maybe 1 n 1?? any advice would be great , thanks happy smoking

well if it's hot already, putting your air off at any point will only make things worse no?
A/C on non stop and it's still hot as hell???? geeez what are you growing in a sauna? lol

if your sucking the cooled air from the grow area then, yes it will be warm. fresh air? plants need water, food, light, and co2, they make o2. if your doing it to keep co2 levels then just go in the arear for a few mins every couple of hrs and breath. i ran my completely sealed rrom for two years befor adding co2.

Are you growing in a cab, closet, room, tent?
Where does your grow area exhaust to? Does it just exit right into the room it is in or do you have it going into an attic or something? If you are just exhausting the hot air from your grow area into the room it is in all you are doing is heating the surrounding area and pulling in hot air, which just causes more heat. Your A/C probably can't keep up. You need to try and get your exhaust routed away from the grow. Either out your window, in the attic, or another room if it isn't already.

You have 2 400+ cfm fans? 1 intake and 1 exhaust? That should be plenty. What type of fans are these? Turn your intake down or take it out, you want more exhaust than intake.

smilebob said:

Are you growing in a cab, closet, room, tent?
Where does your grow area exhaust to? Does it just exit right into the room it is in or do you have it going into an attic or something? If you are just exhausting the hot air from your grow area into the room it is in all you are doing is heating the surrounding area and pulling in hot air, which just causes more heat. Your A/C probably can't keep up. You need to try and get your exhaust routed away from the grow. Either out your window, in the attic, or another room if it isn't already.

You have 2 400+ cfm fans? 1 intake and 1 exhaust? That should be plenty. What type of fans are these? Turn your intake down or take it out, you want more exhaust than intake.

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10x8 room, fresh air is pulled from outside comes under the house and directly into room. exhaust is going up into attic. its been in the 100's all week and the ac is only a 5000 btu so it cant keep up, but even if it was bigger id still have the same prob, they sale a part that i can tie into my fan to control speed and has a couple of other settings but i cant get it yet, so im trying to figure something else out

If you have fresh air flowing in the area, get some big box fans for $20 at walmart. They will help circulate the cool air. I prefer them over oscillating fans. They won't lower the temps much but its an improvement.

a 10x8 grow area is large and hard to cool..... it also is more suitable as a whole for a 4000w system which im assuming you don't have.

-buy some panda poly film comes in 10x100 rolls you just need 10 x 10 ($20)
-buy a couple 2x4 and metal braces ($10)
-frame off a smaller section ideal for your grow size and NOTHING BIGGER than needed to maintain and house the grow.
-take your ac and enclose its blower vent with cardboard and duct tape lots of it in order to funnel down to maybe a 8" duct which you can direct into your under $30 grow tent. use velcro and zippers or just velcro to allow access.

now you can eliminate 1 inbound fan and use either, negative pressure from a fan sucking your light heat out..... or run the ac as your constant fresh air source with your room enclosed and light cooling fan from a separate room.
either way you will probably only need to run the ac in 20 minute intervals on/off on a timer

the goal was less area to cool, less surface that has dark to absorb light to make heat ... everything is shiny white sterile and neat.... and you save money by using 50% less power to run a small 5000btu ac that will not cool a 10x8 in the summer with a 1000w light ... without co2 84-87 degrees is a waste of time growing, you should hit 80 degrees easy with this method again only assuming you have 1000w or less... which in my opinion you dont need co2 supp with good temps and lots of fresh air.

i run a 6x10 room with 2k hps and the first ac was a 5500btu wall/window ac that had no problem keeping temps in check for three yrs. the reason you have issues is you are sucking the cold air out. seal the room. you dont need intake or exhaust.

So you are sucking air from outside? Outside the house? If it is hot outside your pulling that hot air in. Disconnect the intake fan and just use the ac as your intake and see what that does. Maybe move the intake fan so it is a second exhaust fan also.

Put fan speed controllers on your fans. slow down the fans so the ac can keep up.
gotta find that balance that is fresh air but still allows your ac to be effective.
have less air coming in then out. quite a bit less.
if you can give us the wattage and number of lights, outside temps, tent/cab/open, then we could suggest an ac size.

if you are going to do a sealed grow you will need complete climate control.

smilebob said:

So you are sucking air from outside? Outside the house? If it is hot outside your pulling that hot air in. Disconnect the intake fan and just use the ac as your intake and see what that does. Maybe move the intake fan so it is a second exhaust fan also.

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air conditioners recirculate air. They do not bring in air. Although, they are not perfectly sealed, so some air does get passively pulled in.

without an intake, the air is pulled from all parts of the house, which pulls from every little crack, crevice and vent to the outside. You can still get very good buds this way. I did it for years.

Honestly, I haven't seen a huge difference from bringing in fresh air via fan.

HeartlandHank said:

air conditioners recirculate air. They do not bring in air. Although, they are not perfectly sealed, so some air does get passively pulled in.

without an intake, the air is pulled from all parts of the house, which pulls from every little crack, crevice and vent to the outside. You can still get very good buds this way. I did it for years.

Honestly, I haven't seen a huge difference from bringing in fresh air via fan.

Click to expand...

I agree. From the sounds of it though the OP is pulling hot air from outside which will just heat the room up. Only thing I can think of is to move the intake fan to try and pull air from another room in the house, this way the op is still getting their fresh air but it is cooler and the ac won't have to work as hard.
I have a friend who used this method for a few years and he loved it. He just pulled air from a spare room in the house which he kept at 70-72 and used an ac mounted in his grow room to cool the air, and then his exhaust fan pulled the air out. His temps were always between 74-79 during lights on and 69 when the lights were off. His room was about the same size but I don't know what size AC he had.