Equation for venting hoods - watts to cfm

Hey guys I was wondering if in any of your travels anyone has found a general rule of thumb of how many cfm are required to vent x watts in a row. Thanks

A general rule of thumb I was told many years ago was about half your wattage in CFM.
It has worked well for me for 1600 watts and less.
I couldn't tell you if it holds up for higher wattages. I just don't know

i have 2k in a closed system and i have the fan set so the hoods are cool to the touch.

WolfPDestroo said:

Hey guys I was wondering if in any of your travels anyone has found a general rule of thumb of how many cfm are required to vent x watts in a row. Thanks

Click to expand...

With air-cooled reflectors the rule is the cfm rating should be about 20% of the wattage rating combined.

So 200 cfm for 1000w - 120 cfm for 600....and so on. So if you're running 3 600's in a series you'd want around 400 cfm on the exhausting fan, and then probably a small booster at the beginning of the series to help maintain positive pressure. If you were running 3 3000w systems in a series, you'd want at least 600 cfm.

And the more lights in a series, the more the need for booster fans.

Thanks for the input guys. This will really come in handy. Cant wait to vent these hoods and watch temps drop.