# Venting indoor grow room with rooftop turbine vents?



## midibullets (Dec 16, 2009)

Hey everyone!  So here is how i'm venting my grow room currently, and i was hoping to hear from anyone what they think of this, and if you think it will work long term.  From my understanding, turbine vents simply rotate when its breezy outside, thus forcing air from inside the attic to ventilate out that vent.  So if the vent is spinning all the time (440CFM fan always on) or if it is spinning at least sometimes (440CFM fan on a timer or temp control) then i assume the turbine fan will still serve its purpose.  The thing is I have 2 of these things on my rooftop, one spins because my 6" 440CFM fan is venting out of it, and the other is taped still, so that the 4" Vortex 170CFM can pull air from the outside.   Is there going to be a downside with only having one of my Turbine vents working to vent my attic.  Keep in mind, i live in Southern Cali, so weather is pretty much dry and nice all year round so i'm thinking "condesation" might not be an issue over here.  Even right now in December, its 79F


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## meds4me (Dec 16, 2009)

Looks noice other than that the duct work needs to make a nice "seal" to the roof penetration. Use a pc a flat stock ( sheetmetal) and fab up a sq. pc to cover the hole except the duct connection. Also install one in the room as a added protection. ~ Peace and have some fun today ~


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## Bobo (Dec 16, 2009)

meds4me said:
			
		

> Looks noice other than that the duct work needs to make a nice "seal" to the roof penetration. Use a pc a flat stock ( sheetmetal) and fab up a sq. pc to cover the hole except the duct connection. Also install one in the room as a added protection. ~ Peace and have some fun today ~


 
That would look better but remember why the builder put those vents on to keep air in the attic moving. So if u just run the vent out theres no way for the air in the attic to escape. Hence its gonna get hot up there. I would just run the duct work to the attic and not to the vent, unless u dont have a filter and ur trying to blow the smell out.


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## meds4me (Dec 17, 2009)

Usually builders put multiple in OR on either ends of the buildings. The third option is Ridge vents . In any case you probaly have more than one and the concern is HUMIDTY build up in the attic. IF the attic is warmer than the outside air and you vent warm and humid air into the attic space the insulation absorbs this like a sponge. Dont believe , wait til you cieling falls in ~ Hvac exp here....~


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## midibullets (Dec 17, 2009)

meds4me said:
			
		

> Usually builders put multiple in OR on either ends of the buildings. The third option is Ridge vents . In any case you probaly have more than one and the concern is HUMIDTY build up in the attic. IF the attic is warmer than the outside air and you vent warm and humid air into the attic space the insulation absorbs this like a sponge. Dont believe , wait til you cieling falls in ~ Hvac exp here....~



Yeah, i initially had the fans venting into my attic, then within an hour, my whole house had this "attic" smell, so the attic was then venting itself back into my house.  My gas heater even shut off at one point, and has not worked since, which I assume some sort of "vent shutoff" went into place, to make sure a draft was not blowing out the pilot light leaving my house filling with gas.

To remedy this problem, I then ran the grow room outlet ducts straight up to the roof through those Turbine vents.   I didnt seal off the ducting to the vent because I want the vent to still function as an attic humidity clearing device as it were    So in my opinion, putting the grow room air output ducting about 1/2 foot from the turbine vent outlet, it will allow the grow room air to go out of this vent, which spins the turbine vent AND still allows the turbine vent to perform its duty: to vent the attic.  My concern is using the 2nd Turbine Vent as an air intake.  Since those turbine vents spin in one direction, thus sucking air out of the attic, i assumed just tape the "turbine"  from the inside, so it cant move, and then I put the 4" duct right up the 2nd turbine vent, giving me instant fresh air for the grow room.  All around the outside of my house there are small 1/2 foot vents with chicken wire over them so that those turbine vents can pull air from outside.  My room temps went up by 5+ degrees in the grow room due to the warm air from outside being pumped in.  I think it got as high as 80F, which is still in range, but summertime may be a different story!


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## DonJones (Dec 19, 2009)

midibullets,

You are just fine.  If anything extend your ducting on up a little higher into the turbine.

On your attic ventilation issue, remember you have to have incoming air in equal amount to what you want to go out.  MAKE SURE THAT YOU HAVE ADEQUATE INTAKE VENTILATION INTAKE DOWN BY THE EVES.  If you have enough intake area at the eve line, your attic will function like a chimney because hot air rises and the cooler are flows it to take the hot air's place.

Those turbine vents were used because they are cheep and if you have enough wind in your area they will function like an exhaust fan and create a suction that pulls fresh air in through very little hole in the attic.  That to a small extent counters not having enough fresh air intake at the eves, but when the wind stops you're screwed.

Just make sure that you have plenty of intake ventilation available and then see how it works.  

If you want to exhaust the duct directly outside, then have aroof vent installed with a stub sticking down to attach your ducting to BUT leave the attic turbine vents alone before you create a huge problem with your attic ventilation.

Good smoking


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## meds4me (Dec 20, 2009)

Thanks Don for a better explanation ~


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## mistisrising (Dec 20, 2009)

I would only exhaust out that way, and draw from somewhere else. When the summer gets to 90f+, your room will be an oven. IMO, I would just pull from inside the house, and vent into the attic. The six incher going out should be fine without closing off the vent.


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## DonJones (Dec 21, 2009)

mistisrising,

I thought that was what we were all talking about -- exhaust venting.  I haven't heard of any one trying to draw fresh air from the attic, but I guess when you think about how many other weird things happen and some of the strange places people grow, there may situations where the attic is the only source of fresh air.

Good smoking.


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## [email protected] (Dec 21, 2009)

hXXp://www.askthebuilder.com/442_Roof_Turbine_Vents.shtml
Read up may learn something meds.
It's gonna work great mid just fix the turbine vent and put it under the shingles. That silicone is never going to hold.


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## mistisrising (Dec 21, 2009)

DonJones said:
			
		

> mistisrising,
> 
> I thought that was what we were all talking about -- exhaust venting.  I haven't heard of any one trying to draw fresh air from the attic, but I guess when you think about how many other weird things happen and some of the strange places people grow, there may situations where the attic is the only source of fresh air.



Midi said he/she had two turbine vents. One has a six inch going to it to vent hooked up to a 440cfm, and there's a four inch vent, with fan, drawing fresh air from the other turbine. What I meant was that when it's 90 degrees plus outside, it's a hundred on your roof. I thought it would be beneficial to draw the air from in the home to avoid this. NOT from the attic, from a bedroom closet ceiling, or a newly installed vent somewhere.


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## DonJones (Dec 22, 2009)

mistirising, 

I missed that, sorry.  You are correct, draw the fresh air in from a cool source not just a outside source.  Usually inside the house is the most temperature controlled source. 

midibullets,
You really need to get that other turbine untapped so it can do its job.  They put it there for a reason, unless you added them.  If you have a very large house at all, you will need both of them to vent and cool your attic.

Good smoking.


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## mistisrising (Dec 22, 2009)

DonJones said:
			
		

> midibullets,
> You really need to get that other turbine untapped so it can do its job.  They put it there for a reason, unless you added them.  If you have a very large house at all, you will need both of them to vent and cool your attic.
> 
> Good smoking.



If I'm wondering, I assume others might. Is there any sort of guideline to judging how much ventilation you need for your home? Like, a rule of thumb, or something. Or is this best left up to the builder?


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## midibullets (Dec 24, 2009)

DonJones said:
			
		

> midibullets,
> 
> You are just fine.  If anything extend your ducting on up a little higher into the turbine.
> 
> ...



Thanks Don Jones.  As far as air intake for the attic, I do have several 8" square holes that were cut throughout the underside of the roof "overhang" so they can allow air to be drawn in from the outside. They are covered up with some sort of chicken wire to keep the birds out.  I noticed that one of these holes was being used for the bathroom fan exhaust, but other than that the rest are free or have a bit of insulation stuffed near them.  As of now the output duct is spinning the turbine 24/7.   I was going to run both input & output ducts from my grow room to 2 those square holes, but they were too hard to reach.  I could hardly fit up there myself!  I have returned from vacation, and things are still working good and no signs of ventilation trouble as of yet.  Thanks for your input!


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## midibullets (Dec 24, 2009)

mistisrising said:
			
		

> Midi said he/she had two turbine vents. One has a six inch going to it to vent hooked up to a 440cfm, and there's a four inch vent, with fan, drawing fresh air from the other turbine. What I meant was that when it's 90 degrees plus outside, it's a hundred on your roof. I thought it would be beneficial to draw the air from in the home to avoid this. NOT from the attic, from a bedroom closet ceiling, or a newly installed vent somewhere.



Thanks mistisrising.  I didnt think about summertime, and it does get very hot here.  I'll definately have to rethink the intake.  I want to draw air from inside so i'm thinking since i cant cut holes in the walls, i'll just cut another hole in the ceiling of another room and hook the duct that is currently in the turbine vent into the hole in the other room.  I think that should suffice   Thanks for your input!


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