I accidentally, permanently deleted this thread, so here is a re-post:

My grow room uses a 500 cfm inline fan as one of the exhaust fans.
This is my biggest, but in my haste to get it installed, I hooked it up to several reducers to get it through a 3" hole.

Needless to say, the cfm, is most likely alot lower because of this.
So today, I am going to trace the fan, and cut a 8" hole for it.

Temps are usually hoovering around 85 in there on a hot day, around 79 on a better day. Today it's 85 in there.

Lets see what happens after the modification.
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Hey Shaman, its usually around 85 degrees outside.
I am doing a little of both, my home is air conditioned, and I try to pull as much cool air into my grow room. This does help alot.

Placing the reducers on this fan, I feel has severely cut down on my effiency.
We'll soon see.
Peace

I have a similar problem runnig six inches into 4, I may do the same I wanna see how yours goes first....

I'm at about 85 also but my plants are doing fine, I would like to get lower so I can start using my new 600 watt HPS along with a 400watt hps....love

Ok how cool do you keep your house??

__________________
PEACE.
Never stop growing.
Seeds are the future.

I have designed and operated quite a few restaurants over the years,
and I remember in designing the waste water pipes coming from the sinks,
if codes required a 2" drain pipe, and if you enlarged that pipe to say, 3"
that is NOT a 50% increase in flow, I don't remember the exact math calculation, but I do remember that it IS much more than that.
The same principal applies here too.
Peace

Hey my friend, the temp is set at 70 right now.
Peace

I call 74-76 that my bet,

__________________
PEACE.
Never stop growing.
Seeds are the future.

Okay, I am taking a break. I have soooo many tools (NOT) that I had to deal with what I had, an electric knife! LoL
So I want to let it cool down, but I am almost there.
Anyways, here is a picture of the fan I am trying to improve on:
Yes, it is the one in the back.
The one in front is a 4" inline fan with a hose hooked to it, to grab the heat from around the light area.

Attached Images

exhaust.JPG (773.2 KB, 55 views)

SHAMAN, you rock, it is 78 degrees in there now.
Peace