Heat dissapation: How many CFM per Watt?

[masterjointsmith]

come on theres gotta be a good way to caculat that shit

[babystarbud]

theres no easy answer really, depends on more variables than just wattage,

different types of bulb can be warmer or cooler,

also air quality, room size and ambient temps play a roll so the formula would be pretty complicated.

if your using HID;s and can give a room size, it narrows it down a bit

[masterjointsmith]

2x8x8 1000watt mh
ambient temp is 60 in the winter and 70 in the summer

[Joedaddy]

From the Bible:
...Look for an extraction fan with the capacity to change the air once every minute. Capacity refers to the amount of power need to circulate the air volume of your structure. Calculate the volume by multiplying the square footage of your greenhouse by the height. Multiply the volume by sixty air changes per hour to get the cfm capacity...

2ft x 8ft x 8ft x 60 minutes = 7680 cfm

[Tokudai]

7680 CFHour

2x8x8 = 128 Cubic feet ie very small, will heat up quickly

Somewhere around 640 cfm I would start with if you are looking for cooling and air exchange - thats 5x a minute

[invision]

a 600CFM cage fan will keep things cool if you have a vented hood.

[JackdaWack]

i have a 4x8x7 room and a 465cfm cage fan works ok. Could be better a vented hood would really help me out. temps are in the mid 80's summer and now mid 70's for the winter. the winter helps out alot.