Large room , how much cfm

[deprave]

My room is 21ftx6ft and 9ft tall, how much cfm do I need going out, I have a 500 inline going thru about 5 ft of ducting out the roof and it seems weak..what you guys think? It seems powerfull out the top but from the bottom seems like weak pull

 

[desertrat]

you want one complete air exchange per every five minutes to bring in fresh air. if you need ventilation to cool down the room that could increase the airflow needs to as high as five air exchanges per minute. you are at just under 1 air exchanges per every 2 minutes with your current fan, so you're in the middle ground where the amount of ventilation you need will be determined by how much cooling is required.

 

[deprave]

Nice, Yes temps are stable right now 75F to 80F in day...65F to 70F at night...i got a 500CFM fan also intake thru a window that goes outside and a large box fan blowing air around the room

 

[dadio161]

length x width x heigth . You have over 1,000 cubic feet of space.

 

[deprave]

length x width x heigth . You have over 1,000 cubic feet of space.

yep thank you, I couldnt remember how many times the air needed to be refreshed