How much CFM blower for a Cool tube in a 4x4x6.5 box?

[dknob]

Hey if I get a cool tube, with the blower sucking hot air directly out of the box, am I still going to need something powerful enough like 450 CFM? I was thinking 450 cfm because I was told that is ideal for my size box 4x4x6.5 - however, I figured with all the air being pulled out directly from the cool tube, I probably will not need much power to keep it cool and replace the air.

What CFM blower can I get away with?

 

[Eharmony420]

i have a 400 watt hps in a vented hood, the euro hood. I have it in a 4x4x6.5 tent. I only use a 6 inch duct fan from htg for 25 dollars. The tent stays the same as the room with this setup and a passive vent. If it was bigger itwould keep the tent cooler. I plan to put the light on its own circuit and make seperat vent and exhaust. If i cpuld afford it i would have bigger fan..Your 450 will rock the shit outa a 400! That would be perfect especially if it a true inline or squirrel instead of duct fan. It's amazing how well a tent envirnmnet can handle temps. Better than open room. If i open the tent up with light and fan on the tent get cooler than the room. Good luck u ok with that fan!

 

[dknob]

1000w here. Wonder what the heat diff is. Slightly over double id assume. Thanks for the reply, ill check it out.

i have a 400 watt hps in a vented hood, the euro hood. I have it in a 4x4x6.5 tent. I only use a 6 inch duct fan from htg for 25 dollars. The tent stays the same as the room with this setup and a passive vent. If it was bigger itwould keep the tent cooler. I plan to put the light on its own circuit and make seperat vent and exhaust. If i cpuld afford it i would have bigger fan..Your 450 will rock the shit outa a 400! That would be perfect especially if it a true inline or squirrel instead of duct fan. It's amazing how well a tent envirnmnet can handle temps. Better than open room. If i open the tent up with light and fan on the tent get cooler than the room. Good luck u ok with that fan!

 

[Mr. Limpet]

i have a 450 on my 250 watt in a 3x2 and it barely keeps up

 

[BigBud992]

U have a 450 cfm exhaust on a 250w hps in a 3x2x? room and it barely keeps up? What does that mean? Do you vent through a sealed hood? How tall is your grow space? How do you intake? That fan on that light in that size of room is PLENTY enough. My bet is that you dont have enough intake (passive or active). I have a 256cfm booster (160cfm when used alone, which is how I have it) exhausting my 2x5x8 veg closet with 144w of t5 ho flouros and my temps are around 80....but i dont have much along the lines of passive intakes. I'm thinking 2 or 3 four inch pvc elbows will allow me to cool that space to about 72 or so, which is the ambient temp of the room the closet is in.