Need some advice on my inflow / outflow ventilation

I just got done prepping and sealing off my grow closets in my garage. I have 2 rooms both 4x4. For my out flow of air I have a 180cfm squirrel cage fan ( in each room ) with 4in ducts connected to a carbon filter venting in my attic. For my inflow of air I was thinking a re routing a ac duct line (main line goes right over closets in attic) directly into my rooms. Do you think this is a good idea? Any feedback would be appreciated

More air the better.

I like the squirrel cages up in the attic where just a steady flow of air is needed
to vent the attic heat.

Certain apps they work. My concern would be moving more volume of fresh, cool air in
and blasting the hot out. With the right design you can use a big exhaust fan to pull that cool air in
and blow her out.

I run vented hoods and unvented. 4k watts of lights running at night I need a heater
to keep the lab up above 80f. 2 8" Elicients Sucking like a wind tunnel.

Vented Lights kept cool by drawing filtered air from outside and exhausting hot air out.

Up the horsepower on the exhaust.

Just my thoughts,,,,,


bb57^
madds_


ftp

You didn't mention how many watts of light your using...that's the deciding factor here...so, depending on the wattage your burning you may want to re route the a/c or you could use those cage fans to cool your lights then add a third fan venting both rooms and exhausting through a carbon filter. If you go the third fan route, use a 6" centrifugal fan something around 4-450 cfm.

In my flowering room i have a 400w Hps. In my veg room I'm using florescents until I can scrape up some more cash for better lights. Thanks for the tips Boomer and redi

I'm guessing you live in a place that doesn't get too cold? My A/C and Furnace use the same duct work, so for half the year this would work great, the other half it would get hot as hell in there.

Yeah I live in Austin, TX. It never gets cold here, its always about 100degrees outside. But you do bring up a good point. I would never be able to use my heater if for some strange reason it got cold here

I have been using t5 fluoro's that I got from a garden shop that have a blue spectrum, and now I've decided to just keep them rather than get a MH light fixture. they work GREAT for vegging and clones. Plus, they keep the heat and energy bill down.

Well if it did get cold u could install a bypass damper which would close the duct from your ac/heat to another intake source.
Another good point to make here is that your ac's thermostat is inside . So it wont properly work right If its set at 72 then its gonna cool your house to 72 based on where the thermostat is located . It will shut off at 72 but it could be 82 in your grow room still.

I have the same setup a 4x4x7.5 ft in my garage .I have one inline fan in the room pushing air out through the hood and exiting the top.For intake i have an 4 in duct run from my back door to the bottom of my room.The inline fan pulls plenty fresh air in this way for my.I<m north of u though in colorado .Temps cooler here .

If you connect to an AC duct, obviously the fan has to run constantly to stop smell from creeping into the house. When the AC is running, I question whether this will compromise the cooling of the house, running the bill up. May also run the room too cold.
As the Jedi and BB suggested, a fan circuit to cool lights and another to cool the room is most efficient. Just make sure all duct runs are straight as possible and sealed tightly with tape. If you use as much hard duct as you can, you'll find it a little more efficient and considerably quieter. That flex stuff creates a lot more friction and turbulence in the air stream.
Where the two 4in. ducts come together at the filter, you may have a problem with decreased air flow. Some what of a bottleneck there. If you can up the T size and the flange on the filter, you might be ok.
Hope this helps,
Fred