Continuing the discussion from Welcome to the ILGM Grow Support forum:
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The lights will be 1000w each…6×11×7 veg.2 lights…10×12×7 flower 4 lights…
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@Countryboyjvd1971 thanks …this is an idea I had was going with 8 in insulated duct maybe 10 for main everything dumps into…not exactly sure on what fan sizes to use…12in at intake window and 8in at exhaust filters? Is 12 to much? I was thinking big to push air thru all that duct work and lights
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@WillyJ pulling are is more efficient then trying to push it just a FYI
Also you want you exhaust to be stronger than your intake ( make up air) fan
Your want to keep tent , room or whatever your using in negative pressure this will ensure your pulling enough air through
A ten inch round duct is good for around 400 cfm max
Just saw your diagram lol edited this post
Give me a little time to do some calculations and I’ll get back to you bro
I’m at work now sobit may take a little bit but I’ll have it for you today
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@Countryboyjvd1971 My reasoning behind pushing the air was to push make up air into the rooms via same fan cooling the lights…I was thinking larger fan on intake side seeing that I’m dividing that air between fresh air for rooms and cooling lights and taking away for length and bends in duct work …on the exhaust side 1 fan for each room each smaller than the intake fan…the exhaust fans help move the air from the lights thru the exhaust as i would have that air dumping into the exhaust…I was thinking the 2 exhaust fans would pull more air out of the rooms than the intake could push in creating a negative pressure…my other thought would be to put a large fan at the exhaust window and suck air eliminating the need for 2 exhaust fans?
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Ok so for your veg room you have 462 cubic feet and for your flower room you have 840 cubic feet you would want fans capable of moving that amount of air but I wouldn’t run them all the way up get speed controllers
I’m going to make a suggestion that you separate the two exhausts reason being you’ll be trying to maintain two different humidity levels if the rooms so it may just work out better for you
Also looking at you lay out drawing it looks like your planing on one charcoal filter on a separate take off on main duct if smell is a problem for you this wouldn’t work since are being pulled threw hoods would still smell
i would Run fans that Half speed for room size removing to much air is a problem also so in veg tent your looking to remove around 200 cfm which would exchange 100 % of air every 2min
And your flower room you should shoot for about 400 cfm
If you need make up air fans (intake ) go with 1/2 of exhaust speed so in veg 100 cfm and flower 200 cfm
Also if smell is a issue I would mount a charcoal filter on beginning of each hood daisy chain @ least in flower room
You could do exhaust with one main trunk and exhaust blower with dampered take offs on main trunk but balancing air would be hard since air is lazy and will pull from closest openings first
You could have both exhaust from rooms enter a main duct for exhaust out of house
I know separate exhausts are more work but I think you’ll be happier
I have 3fans total in my area one in each tent and one for the room I have tents in all with charcoal filter
I recycle my exhaust air in winter and send it outside during summer the room exhaust help with temps and smells when working in tents
Let me know if I can help with any other questions you seem to be a handy guy @WillyJ
I having a hard time seeing you diagram it get blurry when I zoom in and my eyes aren’t what they used to be
If you want to use one larger fan you need to play with it use dampers on duct runs and try to balance it out could be a pain in the butt
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@Countryboyjvd1971 also I was thinking on diverting the hot air from the lights up into my house in the winter so by blowing air through the lights i would not pick up any smell from the room …if there was any leaks in the lights the air is going to go into room instead of being sucked out of room so the smell would not escape to the house…I heat with oil and wood pellets …seeing that my electric bill is going to skyrocket why waste that heat and save money on the other hand! Lol …in my diagram drawing the main exhaust line starts with a filter fan
@Countryboyjvd1971 being new here they would not let me reply until now. I guess I’m limited on replies in 24hrs…my main exhaust line will start in flower room with a filter and fan go through wall into and through veg room out of other side of room and out window in work area…I was going to run a exhaust fan into main line running through veg room with filter if needed…the lights would be cooled by the intake fan blowing air through them with the hot air from them dumping into exhaust main …i plan on putting a diverter in just before the exhaust main so I can divert hot air upstairs in winter…blowing air through lights will let no smell into house as its separate from exhaust…was hoping a y at the intake will divide the air between feeding fresh air into rooms and cooling lights…hopefully this will explain my drawing somewhat…sorry so long and if I’ve repeated myself … I’ll be taking in all your advice and should be building this next week thanks again…oh and i do plan on using speed controllers, dehumidifiers and will probably be getting a environmental controller
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Ok cool @WillyJ yeah as you read more and post more your trust level will go up and you’ll be allowed to post and what as much as you like
I must have missed it earlier that you planned on pull cool air from outside of room threw lights good idea 
Let me make one more suggestion bro try putting inline duct booster fans after light to draw air from outside and then blow into main exhaust duct
They are cheap you can pick up 6inch duct booster fans that move 250 cfm for maybe 40$ at the box hardware stores
Your set up sounds good otherwise
You can try to blow and with exhaust running it should work fine but keep in mind exhaust should be more powerful then the rest of your fans
Keep me posted my friend
Happy growing
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@Countryboyjvd1971 thanks man I appreciate the advice…I will keep the inline boosters in mind…I’ve decided to go with 8in duct to cool the lights and use 10in for exhaust main… a 6in fan and filter to exhaust veg room which will dump into 10in main…do I really need a charcoal filter for the veg room?8in fan and filter for the flower room attached to the beginning of the exhaust main the exhaust from the lights will also dump into exhaust main in summer…in winter it will be diverted upstairs (before exhaust main)now to decide what size intake fan to feed fresh air into rooms and into lights to cool them…I want to use 1 fan to do this job and divide the air to do both jobs…I will use speed controllers to dial everything in…and the booster fans to help if needed…I plan on starting this build this weekend I’ve got three plants growing under T5 lights and need to get this thing built! I got sour diesel from ilgm, critical cheese from a friend,and a purple train wreck from a seed I got from a bag…I have more sour diesel seeds and a few more critical cheese seeds for when i finish rooms…then I’ll try my hand at cloning once I get rolling…I’m going to try and put a pic up of the 3 i have growing
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Sounds good brother let me know how it works out there’s always more than one means to a end 
CB
I’ll be watching for pics
Need to figure out how to resize pic…I hit upload take a pic and hit ok and upload and it says file to big to resize…not to savey with this stuff lol
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@Countryboyjvd1971 the first one is critical cheese the second is a ilgm sour diesel and the third is from seed I found in a bag of purple train wreck …that ones about 20 days older
Looking good @WillyJ
Your going to have some nice plants from the looks of them now brother
Happy growing
I’ll be following your grow CB
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@Countryboyjvd1971 I was rethinking everything and took your advice and going to pull the air thru the lights …I’m going to use a 10in fan for that…I’m going to exhaust the rooms with a 8in fan with 8in duct to the filter in veg room and reduce it to 6in duct and run that into flower room and leave it open…you said I should shoot for removing about 600 cfm between the 2 rooms and a 8in fan will remove 590 so I probably want to bump that up to 10in? I’m going to add a filter to the 10in fan and divert the air from the lights upstairs in the winter…(not in my drawing)I’m going to run passive vents from each room feeding from the intake window with hepa filters before the rooms…this should give me my negative pressure…and I will be using speed controllers, dehumidifiers with environmental controllers and a light controller that I can run 2 light cycles so it will run both rooms…I think this is much better…what do you think? Your advice has been very much appreciated… WillyJ
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