You would think companies that market these products for "horticultural uses" would know enough about the product to give first time consumers the proper information.
A 440 CFM rating is not adequate for a room measuring 400 cubic feet. Had I known this, I would have spent the extra $80 for the 800 rating along with larger filter.
Now I have to buy a second one.
You have to allow for performance loss due to restrictions placed on the ventilation system by various things such as
Carbon filter - up to a 25% efficiency loss.
Ducting runs - I think its something like every 10feet of ducting reduces around 5% efficiency.
Bends in duct work - every 90 bend is a 20% loss.
Lighting. 600-1000w - add 15% to your room cf for open reflectors. 5% if air cooled using the fan.
So for example. To do the job with a 1000w open reflector in a 400 cf room.
400/100 = 4 =1% of the cf. 4*15= 60. So our fan currently needs to be 460.
4*25 = 100. This allows the carbonF to be attached. =560
With one 10Ft duct run. 4*5=20.
20+560=580.
So in order to ventilate your room and cool the area with the chosen 1k light you need 580CFM of fan power with matching or higher CFM filter.
That's how I would have personally worked out the area for ventilation.
J