Help Needed involving exhaust and intake, 6.5X8X8

Help me out!

6.5w 8long 8 high, lots of reflection

Here's my setup so far, I've got a 1000w light for the grow area. And right now I have a 450cfm approx. inline fan which I was planning on using for exhaust and cooling the light, the air coming in would be from a window outside the sealed grow box through ducting. I was going to set the inline fan to bring in air from the grow box and force it out into the attic which has an open window.

HERES THE QUESTION
Do I need to get an exhaust and intake fan and have two running? Right now I have 450cfm inline exhaust through 6'' ducting cooling the light in a sealed reflector at the same time. Will the air through another duct be enough to passively intake air?

The great thing is this is 215 legal.

i dont really know shit im just starting like you ive grown outdoors before . this is my first indoor . but i had similar ?s . if i was you i would just start with the exaust fan because it should suck in fresh air to replace the discharged air thats what im doing my temps arent as bad as i expected if its still to warm then and the intake you can see mine in the indoor section under the thread about the 6x8 tin shed scrog good luck

thanks man. I don't think I'll have a problem with warmth though, it gets pretty cold at night and I've got a heater. I'm concerned really If a 450cfm is powerful enough to replace the air in the room every 5-10 minutes through the reflector, and intake through 8'' ducting.

By your dimensions, you have 416 cubic feet of grow space. Let's say you want to exchange the air in your room every 5 minutes. So you divide 416 by 5 and you get 83.2. So basically any fan capable of 83 CFM or greater would work for ventilation.

Your fan is 450 CFM. It should have no problem cooling the hood and venting the room through the intake side of your reflector.

thanks that was what was looking for, just worried about the intake but that pretty much answers my question. looking forward to getting started in a couple weeks.