- if you get your house temp lower than 73 it should make a significant difference in your room temp. - A bigger fan sounds like a great idea. put it at the end of all of your ducting, think about pulling the air through the ducts and pushing into the attic (wherever you are venting it to), not trying to push it from inside the room all the way through those twisted ducts. you could even use the 6" in front of the cooltube sucking air from the room and pushing it across the bulb into the ducting. - for stealth reasons you should think about a carbon scrubber to attach before the cooltube as well. this is where the second fan (sucking through the scrubber, pushing across the bulb) would really come in handy. as long as you can keep the grow room temps in check, you don't need to follow Raoul's (5 x room volume per minute) air exchange rate. as long as fresh air is constantly flowing in and temps are comfy the plants will be happy. IIRC, Jorge Cervantes recommends a 1 x room volume/minute exchange rate for happy plants. EDIT: reread your post, seems like you're doing the exhaust opposite what i suggested above. Give it a try both ways, I'm personally not knowledgeable about whether it's better to have BIG==small or small==BIG. Vashigopal probably knows better
really the exhaust hole is only 4" while the intake is about 9"tall and 4"wide i have a 6" inline but i have two 6"-4" converters on both sides i just straightened out the ducting out a lot and i feel like its helped a bit already. a carbon scrubber was already on my to do list. would it need to be in the front as you suggested or could i attach it to the end like i planned?
u should use both fans for exhaust. use the big one to vent the cab, use the small one to cool the bulb. give the small one its own intake, make more passive vents around bottom of cab. it will be neccecary to scrub/ filter air from large exhust only if you bring fresh air into cool tube and vent without smell. hope that helps
I've been reading a lot of threads recently about high temps (for some odd reason). I notice a lot of ppl try to vent these operations in a 1 step solution. That is try to exchange the grow room AND cool the lamp with a single fan. It would seem to me to run two fans - I mean they are kinda cheap. One fan to (House) -> (Duct) -> (Reflector) -> (Duct) -> (Fan) -> (Duct) -> (Outside) And a second (Scrubber) -> (Duct) -> (Fan) -> (Duct) -> (Outside) With the House air venting into the grow room.
ok so are you suggesting: intake > 6" fan > bulb > exhaust and then having a separate setup also with different intake > room > exhaust > 8" fan > carbon scrubber ? (by the way the > is like "to" or "followed by" if you didnt catch that) also, would this setup eliminate my 9" intake fan? my room is pretty much 100% air tight so when i cut that fan on, the air in the room has nowhere to go except the exhaust. my problem is its not flowing out that exhaust as quickly as i'd like and is ballooning out the mylar. if i were to put in some passive intakes as you've suggested, i fear that the air will just flow in my 9" intake and then back out those. also, youve got to remember that my room is surrounded by walls on 3 sides. so really all i have to work with is the front side (which is 70% door) and the top.
not a bad idea, and i definitely plan to have 2 exhaust fans soon regardless of the setup. i know you pretty much just went against a 1 step solution, but what if i were to put it all into one line of ducting: carbon scrubber > fan > duct > reflector > duct > fan > duct > outside that way since i already have air from the house forced into the room from the 9" intake, i would only need one thing of ducting. i think the real benefit to your solution is the fact that cool air, rather than the hot air in the room, would flow across the bulb. and thats the only thing my setup really seems like its missing. the only problem i see with your solution the way my room is set up is that im running the exhaust ducting across my bathroom and then out the square hole in my ceiling where the bathroom fan usually is. im not sure id be able to fit two of the 4" ducts through there.
lol on the > instructionalok i went back & looked at the pics.i would say you have a few options,i would definatly go ...intake from household air >duct>cooltube>duct>exhaust fan>outside.this will remove the majority of bulb heat.if u can mount your ballast by the intake on the outside of tent it will draw air across the ballast & vent the heat outside w/bulb heat for greater cooling.now the larger fan can be used to exhaust the growing space for additional cooling & air circulation this is how i would set up second system...first put exhaust vent in top of tent if possible or top of doorjamb,opposite from passive intakes if possible.then go exhaust vent>duct>fan>scrubber.this can be recirculated into house if nececary(you'll be first to know when the filter needs changing)or vented outside(this may be neccecary if heat probs persist after cooltube is vented correctly) also mount ballast outside room if possible.you can mount small pieces of duct to passive vents to bring air to back of room.you may need a bigger exhaust port to outside.
Use no intake fan. Run everything as exhaust and just have passive intakes. That should be able to easily cool it to ambient. You could also try using a sealed hood for the light and vent it with one of your high pressure fans.
ok so how would i attach another piece of ducting to the socket end of the cool tube? just cut a chunk out of the end of the ducting to make it fit past the bracket connecting the socket to the reflector? i guess you never finished post? anyone know if theres a ducting connector that would convert 2 ducts to one?
been reading along... although your DIY engineering on that cool tube is indeed admirable, i can't help but think that simply investing in a sealed hood (as has been suggested by bulletcatcher already) may be worthwhile for what you're trying to do. sorry, i know that didn't exactly answer the questions you posted. but i think it'd make your life easier.
If you look at my avatar,those are CFL's and my profile explains how many and wattages,but the point is,they are a lot less heat than than hps or mps bulbs and require no extra cooling on my cabinet. They also only draw about 1/3 of the electricity while pushing lumens equal to 800 watts of mps. I have 4 computer cooling fans mounted on the cabinet and the temp in the closed cabinet runs appx 5 to 8 degrees warmer than the room temp. I would say that the hps/mps lights may improve the size of your buds slightly but since my goal when I built it was not to buy any marijuana and support the cartels,they do a very fine job.
Everything I have read says 80 to 90 degrees,as long as you stay below 95 degrees where most sativa strains shut down. I don't know what temp indica will shut down but I have never tried yet to grow indica. My cabinet runs at 80 to 87 degrees,according to my hi/lo thermometer.
There really is an easy solution to what seems like a big problem. It's very simple really,i will need to know the intake temps first though???? All fans have a CFM rating which depending on what type of fan it is will depend on just how it will hold that CFM rating under load. The rated CFM of a fan is alone,no ducting,no turns,no reducers(reducing will dramatically reduce that CFM too),no cool tube and no CF....alone. 450 CFM is a better choice IMO and your fan choice is not a good choice at all as those are only booster fans used to help move air longer distances.(they bog down the CFM as soon as you add any load to them at all. One 6" true inline can type fan will exchange all the heat that 400w. HID puts out IF your pulling cool air(75f. or below)from the intake. The exchange rate of that 3 fan system is VERY low and one good can fan will fix it if the intake temps are 75f. or lower. If they are not you could use a closed system with the two inline fans just for the light pulling air from the top of the room through the cool tube and out and a real fan at the top of the room(or better yet in the attic) pulling hot air out through a CF at the top of the room. Passive intakes should work if your area is double the exhaust. GL OCI
i finished my post now. check it out.sorry i had to go.you can make a slot in the ducting for cord &bracket.then tape over it after it's in place,this will keep all air in tube.you can get Y connecters for ducting ,but if u try to push too much air through one duct you will create too much back pressure on the fan,causeing overheating.
intake temp running at 75f right now. yea i hadn't done quite enough research when i started buying stuff. a friend of mine suggested an inline duct fan. i figured out later it was really a booster fan. wont a true inline cost me like $70 minimum? should i look at getting that rather than another booster to add on that's half the price?
If you have central a/c, that's great. Using the bathroom vent for exhaust is clever, but does that mean there's no ventilation when you take a shower? May not be a problem if you have central a/c, but you might want to put a fan at the door to help the humid air get out of the bathroom. Would it be possible to cut a hole in the ceiling, in or near the grow room, to eliminate much of the ducting, and get the ducting out of the bathroom? I agree that you don't need an intake fan unless it's doing double duty as a circulation fan, or if it's pointed upwards towards the lamp intake. (I did that for my light, and it helped 1 or 2 degrees.) Right now you're limited by the size of the intake on the socket end of the cool tube, and the length and turns of the ducting. The intake fan can't help to "push" air out. Your exhaust fan(s) have to pull air out. I agree that a bigger hood (instead of the 4" tube) would be less restrictive. I think you'd be ambitious to get your grow room 5 higher than the house temp, and it's a goal to shoot for. From what I've read, 75 is the ideal temp for MJ, and higher than 81 or 82 will decrease your yields, unless you're using supplemental CO2. As ocitown said, the CFM rating of a fan is measured in "free air" with no static pressure. The static pressure capability of the fan is important when you have to pull air through a scrubber, cool tube, ducting, or any other obstructions. Many manufacturers don't give the static pressure ratings, but the good ones will give you a curve (I think it's called a P/Q curve?) that shows the cfm at various levels of static pressure (which is measured in mm H2O, or inches H2O, or Pa). Sometimes a fan will have just one number for static pressure, and that would be the pressure at which the fan stops. In general, the more power a fan uses (the higher the watts), the better the static pressure capability, all other things being equal. But some fans can be crappy quality, use more watts, and not work that well, so it's not a hard-and-fast rule. For this fan, Soler and Palau TD-100 4"/100MM Inline Mixed Flow Duct Fan The static pressure ratings are on p.8 of this brochure: http://www.fjevans.com/fjeec/images/pv-bathroom.pdf BTW, do you have an electronic ballast (I think I see one in the picture)? How do you like it? Does it get very warm?
i absolutely can not cut a hole in the ceiling hah my leasing agency would kill me originally i had planned on exhausting out where the light is in my closet, but i took the light housing down and it turns out it was mounted to some 2x4's behind it and i cant get through them. the next option was my bathroom fan. i begun taking it down and lo and behold, it was connected to absolutely nothing and was just sitting in the hole. yea i have central a/c. im not worried about the humidity when i shower though cause its only like 31% tops. i also have a floor fan blowing the air from my room into my bathroom which ive never showed you guys. didnt really think it was necessary. ive heard supplementing c02 will help with any yield regardless of the room's heat. is this true? and would making a little yeast bottle be enough to supplement c02 in my situation? ok i will definitely be buying a second fan. i guess my real question now is: would it be worth my time to buy another cheap booster fan to raise the cfm's a bit, or should i fork over the $100 for a good centrifugal fan? money is somewhat of an issue for me at the moment as i have already spent hundreds on my setup. if it is possible to achieve the same results using 2 cheaper fans, i would almost prefer that. from what everyone seems to be saying though, i shouldn't cheap out with my fan. everyone also seems to be saying that while my diy cooltube is neat, it seems to be too small. if i were to fix this issue instead and buy a better reflector it would still cost me like $120, which is more than i spent on my lighting to begin with. at the moment, i just dont have the necessary money to fix both problems it seems. i can either buy another fan, or buy another reflector (i really only want to get that reflector if you think its ABSOLUTELY necessary because i will have wasted the money on this other one) thanks again for the help everyone!
search mechanibus ;$20 DIY cooltube.theres info on making a 5" cooltubu & a link to cheap cooltubes too.ok where does air going thru hole in bathroom go?how big is the opening where the fan used to be?if it vents to attic then outside(screened attic vents should be visable)you can use as big ducting as will fit & 1 good inline(as large as you can afford up to bathroom vent size)but if u try the way i recomended first you might get by,especially if u can vent both out thru bathroom cieling
I should have noticed this before, but you could mount your light higher up to eliminate some of those bends and some length of ducting. You'll have to put your plants on crates or boxes or something to get them closer to the light. When you say the bathroom fan was connected to nothing, do you mean no power, and no ducting? The grate that the bath exhaust goes to -- is it on the side of the house, and how far above the fan opening is it? The 5" tube is a great idea. You would need to replace your ducting and the reducers/enlargers, but it will increase the area for airflow by more than 50%. Even if you have to reduce it back to 4" for the bathroom hole, it's still worthwhile because because the speed of the air has slowed by the time it gets to the bathroom. The bathroom hole might be a good location for your second fan. Actually, the 5" tube is better even if you only replace one reducer (one of the 6" to 4" reducers replaced with a 5" to 4" reducer), without replacing the ducting. The reason I think this is because the socket end of the cool tube seems to be your biggest restriction to air flow at this point. Since this is your intake for the light, it should have the biggest opening possible. But of course if you can use 5" ducting it would be better. Another thing -- if you live in a rental, how often does the management come inside your residence? Have you thought about how you're going to disassemble your ducting in a hurry?