Extraction for 1200 watts?

[quitelost]

Could someone please tell me how many CFM one would need for 1200 watts bare bulb with a passive intake?

Thanks,

ql

 

[irishdude5186]

Hey quitelost, well we can't really answer that for you. First off as you probably know already CFM is cubic feet per minute. This is the pace at which volume of air is moved. So you need to determine the volume of the room you are working in and how much you would like the air to be exchanged per minute. So for example like a 6' x 6' x 6' = 216 cubic inches. The rate of air exchange per minute is recommended to be twice per minute by prominent ICMag members like DHF. So if you took a room the size of 216 cubic inches and you wanted the air exchanged 2x a minute you would need a 432 CFM or nearest fan size. This helps the plants to stay healthly with sufficient Co2, helps the plants develop sturdy stems, less chance for pests to develop and helps keep humidity/heat in check.

 

[Big Brotha P]

To add to this, ambient temps should also be a factor when deciding what size of fan.

I would say "more" of a factor than just size of grow room. Is the grow in a basement, garage, attic? You might need more cfms.

Sizing your fan to the size your grow room has been a generic formula growers have been using for years. Sometimes it works (nov-april temps) often it doesn't (summer temps). Often you'll find growers with large inline fans but still need a/c systems. How is this possible? I thought they sized it right? lol..

Air circulation (2x per min) plays more into controlling humidity then temps.

I'm getting all technical and such. Thermodynamics is what it's all about.

Also make sure your dumping that hot air somewhere outside or your going to need a/c.

I like to match inline fans with duct booster fans, as passive air intakes normally lower inline fan cfms due to them rarely sized right.

Have a good one friend.

 

[DHF]

Hey quitelost, well we can't really answer that for you. First off as you probably know already CFM is cubic feet per minute. This is the pace at which volume of air is moved. So you need to determine the volume of the room you are working in and how much you would like the air to be exchanged per minute. So for example like a 6' x 6' x 6' = 216 cubic inches. The rate of air exchange per minute is recommended to be twice per minute by prominent ICMag members like DHF. So if you took a room the size of 216 cubic inches and you wanted the air exchanged 2x a minute you would need a 432 CFM or nearest fan size. This helps the plants to stay healthly with sufficient Co2, helps the plants develop sturdy stems, less chance for pests to develop and helps keep humidity/heat in check.

Excellent post ID , and dead on except that`s not inches but rather ft and I`m sure that`s whatchas meant ta say , but.....

As BBP pointed out about "thermodynamics" coming into play , said grow area needsta be well insulated as well as exchanging air twice per minute ..and.....

Major air extraction plays just as much a part in controlling ambient temps by keeping environment totally in check once dialed but.....

I preach "active" intakes on "speed controllers" so as not to overwork the exhaust/scrubber combo`s , as well as not pushin too much air into the grow area and creating "positive" instead of "negative" pressure cuz positive pressure will push stank air out through nooks and crannies and smell outside the grow area is a no no......aight.....

Holler if I can help , but the above posts go a long way in determining where yas wanna start and end up so......

Good luck and.....

Peace....DHF..........

 

[quitelost]

Also make sure your dumping that hot air somewhere outside or your going to need a/c.

I can't just use the heat to warm the apartment during the winter?

 

[DHF]

I can't just use the heat to warm the apartment during the winter?

Yes.....it`ll help but don`t know how much......

What he meant was to get the heat gain away from the grow area constantly and consistently.......

Peace.....DHF...........

 

[Big Brotha P]

I can't just use the heat to warm the apartment during the winter?

Yes, I heat part of my home in the winter months.

Just have a plan for the summer to exhaust the heat from the building. Or pay for a A/C and the electricity.

Good Luck.

 

[irishdude5186]

Thanks BBP\DHF! oopsies on the typo.. BBP, excuse my ignorance..I live in Ireland by the coast which has a huge moderating influence on my local temps.. my summers rarely get over 70F. A/Cs are for yey yanks Heating is what gives me heataches. God bless Turf/Peat.

Be wary of the security implications when heating your own house with your grows exhaust because windows with constant condensation is a dead give away.

If you are using passive intakes to your room make the hole at minimun 10% larger than the surface area of your exhaust. I know lots say 50% but ventilation mate of mine told me at a min 10%. No harm making them 50% I guess. So for example if using a 6' exhaust, use Pi*r*r ((3.14*3*3)square inch) to calculate the area and add 10% min.

 

[Canada]

I had a friend that got schooled on growing in Missions British Columbia tell me one day that the key to his 2+ lbs a plant (4 month grow cycle) was the negitive pressure of the room . Im not sure if his thinking was correct, but it made sense to me .

He told me that the room has to have suction ( neg pressure ) to really get the buds swelling . He went on to tell me the suction in the room draws the "juices" up to the surface of the plant which makes nutrient uptake more efficient and makes the underneaths of the leaves "breath "better; . He said it was like when a girl sucks on your skin leaving a hickey it just pulls everything to the surface .

 

[Fly by Night]

2x600=6in vortex

2x600=6in vortex