# Air Cooled Hood vs. Cooling The Room



## BoneMan1000

I have one issue that's troubling me and I keep flip-flopping on which way to go. 

It seems that an air-cooled hood has the advantages of being able to keep heat down from the light's output, increase bulb life, as well as allowing you to place the light closer to the plants. The negatives are that the glass in the hood can cut the lumen output by up to 10%, and also having air move across the bulb can cause a voltage drop decreasing light output even more, up to 25% total loss of lumen output with this setup.

With that being said, wouldn't a grower be better off by controlling the temperature in a tent (for example) with solely a powerful speed controlled fan maybe in combination with controlling the temperature in the room, outside the tent? Of course you'd use a batwing or some other type of simple reflector instead of an air-cooled hood. On paper this seems to be the best way to go but I could be completely wrong, that's why I'm asking. Thanks.


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## bwanabud

I think you will have serious heat issues...plus the vented light is giving air exchange for plant growth.

A vented lite only increases ambient temp by 5% or so...the amount of ventilation needed inside a tent, without cooled lites....will be a wind tunnel...JMHO


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## BoneMan1000

bwanabud said:
			
		

> I think you will have serious heat issues...plus the vented light is giving air exchange for plant growth.
> 
> A vented lite only increases ambient temp by 5% or so...the amount of ventilation needed inside a tent, without cooled lites....will be a wind tunnel...JMHO


 
It's gonna be a 1000w light in a little bigger than a 4x4 tent, so I'd need to be sucking out a lot air in order to cool the tent without an air-cooled hood. Thanks for that.

I'm not sure about your comment about air exchange. If I go the air-cooled hood route it would be setup: (FILTER)--->(FAN)--->(HOOD)--->(DUCTING)------>. 

Without the air-cooled hood: (FILTER)--->(FAN)--->(DUCTING)------>. 

It seems either way the air exchange would be the same? Thanks.


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## pcduck

I run mine filter>Hood>fan>exhaust and place ducting where needed. I pull instead of push.

I was wondering where you got your information on the total loss of lumens when using a/c reflectors? That seems like an awful high percentage loss for going a/c to me.


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## OGKushman

IMHO if I had to do it all over again....4ft parabolics and a mini split


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## BoneMan1000

OGKushman said:
			
		

> IMHO if I had to do it all over again....4ft parabolics and a mini split


 
Thanks, can you explain what this is? Don't know what a "parabolic" is or a "mini-split". Thanks.


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## OGKushman

Hehehe

Sorry, If I had to start over with no equipment I would spend the ~1200$ on a mini split Air conditioner, and instead of sealed glass hoods I would buy open "parabolic" hoods.

I would have saved 4-500$ on expensive hoods and spent that towards a proper cooling system that could cool the open parabolic hoods.


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## BoneMan1000

pcduck said:
			
		

> I run mine filter>Hood>fan>exhaust and place ducting where needed. I pull instead of push.
> 
> I was wondering where you got your information on the total loss of lumens when using a/c reflectors? That seems like an awful high percentage loss for going a/c to me.


 
pcduck, It was from a video with a lighting pro. I tried to relocate it but can't find it. The common knowledge is that light is lost from having glass in the hood, but what was new in this video was the claim of a voltage drop from having air flow across the bulb. Something about the "arc" inside the bulb. I'll keep trying to find it and post it if I locate it.


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## BoneMan1000

OGKushman said:
			
		

> Hehehe
> 
> Sorry, If I had to start over with no equipment I would spend the ~1200$ on a mini split Air conditioner, and instead of sealed glass hoods I would buy open "parabolic" hoods.
> 
> I would have saved 4-500$ on expensive hoods and spent that towards a proper cooling system that could cool the open parabolic hoods.


 
OGKushman, So a "proper cooling system that could cool the open parabolic hoods" would mean cooling the room instead of cooling the hoods, like I mentioned in my original post? Thanks.


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## BoneMan1000

pcduck said:
			
		

> I run mine filter>Hood>fan>exhaust and place ducting where needed. I pull instead of push.
> 
> I was wondering where you got your information on the total loss of lumens when using a/c reflectors? That seems like an awful high percentage loss for going a/c to me.


 
Here's the video I was talking about. It's later in the video where he discusses light loss from air flowing over the bulb:

hxxp://www.youtube.com/watch?v=TUPlaKadogc&feature=relmfu


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## pcduck

I agree with OGK a proper cooling system is the best way to go for many, but it really depends on the growing conditions of each individual grow. And the cost involved to maintain the system.

 As an example:My ac could never keep up with the heat of two 600's in my tent, without a/c hoods. My fan already sucks in the sides real good, so a bigger fan might collapse the tent. Having an intake air temp. that was cool enough to accomplish this without a/c hoods is detrimental to the growth of the plant in general.ime


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## BoneMan1000

pcduck said:
			
		

> I agree with OGK a proper cooling system is the best way to go for many, but it really depends on the growing conditions of each individual grow. And the cost involved to maintain the system.
> 
> As an example:My ac could never keep up with the heat of two 600's in my tent, without a/c hoods. My fan already sucks in the sides real good, so a bigger fan might collapse the tent. Having an intake air temp. that was cool enough to accomplish this without a/c hoods is detrimental to the growth of the plant in general.ime


 
I never knew about the collapsing the tent issue. I'm leaning towards an air-cooled hood. Thanks.


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## pcduck

Yeah I have  6" Vortex on a speed controller pulling through ducting,a wye then through 2 lights another wye,ductting, then to the carbon filter and it still sucks in the tent really good.


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## BoneMan1000

pcduck said:
			
		

> Yeah I have 6" Vortex on a speed controller pulling through ducting,a wye then through 2 lights another wye,ductting, then to the carbon filter and it still sucks in the tent really good.


 
pcduck, what's the cfm of that fan?


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## pcduck

BoneMan1000 said:
			
		

> pcduck, what's the cfm of that fan?



Vortex High Power, 449 CFM 6 inch Inline Fan

purchased from here:

plantlightinghydroponics.com/vortex-inch-449-cfm-high-power-inline-fan-p-353.html


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## BoneMan1000

pcduck said:
			
		

> Vortex High Power, 449 CFM 6 inch Inline Fan
> 
> purchased from here:
> 
> plantlightinghydroponics.com/vortex-inch-449-cfm-high-power-inline-fan-p-353.html


 
Thanks, I'm looking at similar type of fan, 6"/ 424 cfm. I'm gonna get a speed controller too. I am glad to hear that that size fan is plenty powerful enough.


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## bwanabud

Stick with the 6" PCD recommended....I bought the Vortex 8", it'll suck the chrome off a trailer hitch ball


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## nouvellechef

I would say it depends on the state you live in really. Hands down air cooled hood over cool tube.

OG is correct for his state. Sealed room running a mini split or frost box and CO2 in parabolics or the large bat wing reflectors suits a state that has high temp issues throughout the year. Here like in WA. Outside air can be pulled virtually 12 months a year thru the aircooled hoods and not bat an eye over 82 or so. Cooling with air will vastly be cheaper from a net cost(your cost) per gram of bud produced. However it could be argued that a sealed room will always yield more than a outside air cooler room. I see it every year in July/August in veg and flower. They just grow "harder" from the elevated CO2.

Sorry long response. I would go with air cooled hoods(local depending). I also dont think CO2 is right for a grower that has not mastered the piece of how to grow a plant and have it lush at harvest time w/ no problems the entire cycles either. Baby steps


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## bwanabud

Yea, dat ^^^


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## BoneMan1000

nouvellechef said:
			
		

> I would say it depends on the state you live in really. Hands down air cooled hood over cool tube.
> 
> OG is correct for his state. Sealed room running a mini split or frost box and CO2 in parabolics or the large bat wing reflectors suits a state that has high temp issues throughout the year. Here like in WA. Outside air can be pulled virtually 12 months a year thru the aircooled hoods and not bat an eye over 82 or so. Cooling with air will vastly be cheaper from a net cost(your cost) per gram of bud produced. However it could be argued that a sealed room will always yield more than a outside air cooler room. I see it every year in July/August in veg and flower. They just grow "harder" from the elevated CO2.
> 
> Sorry long response. I would go with air cooled hoods(local depending). I also dont think CO2 is right for a grower that has not mastered the piece of how to grow a plant and have it lush at harvest time w/ no problems the entire cycles either. Baby steps


 
Thankyou, I'm all straightened out now. Air-cooled hood and 6" fan. I'm in the northeast USA, Massachusetts, so that seems to fit your recommendation. Thanks for taking the time, and thanks to everyone. 

BTW, great site you guys have going here, very laid back and helpful. Just another example of the terrific medicinal qualities of our favorite herb.


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## BoneMan1000

bwanabud said:
			
		

> Stick with the 6" PCD recommended....I bought the Vortex 8", it'll suck the chrome off a trailer hitch ball


 
I could say something here but I'm gonna restrain myself lol. :hubba:


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## bwanabud

BoneMan1000 said:
			
		

> I could say something here but I'm gonna restrain myself lol. :hubba:


 
Yep, yep, yep ....I know, great minds think alike  :hubba:


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## superdaddy6

BoneMan1000 said:
			
		

> Thankyou, I'm all straightened out now. Air-cooled hood and 6" fan. I'm in the northeast USA, Massachusetts, so that seems to fit your recommendation. Thanks for taking the time, and thanks to everyone.
> 
> BTW, great site you guys have going here, very laid back and helpful. Just another example of the terrific medicinal qualities of our favorite herb.


nice too see another northeast grower here.


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## LEFTHAND

BoneMan1000 said:
			
		

> The negatives are that the glass in the hood can cut the lumen output by up to 10%, and also having air move across the bulb can cause a voltage drop decreasing light output even more, up to 25% total loss of lumen output with this setup


 
*WOW ...*
*thats alot of lost lumens. means my 600w 90k bulb looses 22,500 lumens.. lol...*
*im a lil sceptical on this..*

*LH*


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## Hushpuppy

I have been doing electronics for about 20 years and have never heard of anything like that. I can't see where air blowing across the bulb would cause a voltage drop. Maybe if the inner bulb were exposed to rapid cooling where it couldn't maintain the necessary temperatures to properly fire the gasses within, you then could have considerable losses, but then the bulb would probably fail pretty quick. I am willing to bet that is **.


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## LEFTHAND

Hushpuppy said:
			
		

> I have been doing electronics for about 20 years and have never heard of anything like that. I can't see where air blowing across the bulb would cause a voltage drop. Maybe if the inner bulb were exposed to rapid cooling where it couldn't maintain the necessary temperatures to properly fire the gasses within, you then could have considerable losses, but then the bulb would probably fail pretty quick. I am willing to bet that is **.


 
*i figured as much hush...*
*from what i gathered and got from that video was that its his new product and hes trying to "sell" em...:ignore: ..... "the wave of the future"  lol......*
*LH*


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## gourmet

I have a 3 speed can fan and had to put the filter on the outside of the tent.  So I pull the air out of the tent through the filter.  On the other side I have the tent right next to the outflow of a window air conditioner I use to air condition my bedroom.  The temp fluctuates between 72 and 78 generally, usually staying close to 74.  I have changing the temp on the air conditioner to an art depending on the weather outside.  I just don't have the extra electric to put another exhaust fan for the light itself.  This seems to work fine for me.


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## BoneMan1000

LEFTHAND said:
			
		

> *i figured as much hush...*
> *from what i gathered and got from that video was that its his new product and hes trying to "sell" em...:ignore: ..... "the wave of the future" lol......*
> *LH*


 
My thinking after watching that video was _yes_, he's trying to move product, but I also thought that there's some truth to what he was saying but that he cooked the percentages.


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## sMACkaddict

BoneMan1000 said:
			
		

> My thinking after watching that video was _yes_, he's trying to move product, but I also thought that there's some truth to what he was saying but that he cooked the percentages



ahhh buzz kill, keep it to yourself PLEASE


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## BoneMan1000

sMACkaddict said:
			
		

> ahhh buzz kill, keep it to yourself PLEASE


 
Oops, sorry, I knew after writing it I chose the wrong analogy. A buzz kill indeed.


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## sMACkaddict

BoneMan1000 said:
			
		

> Oops, sorry, I knew after writing it I chose the wrong analogy. A buzz kill indeed.



Haha lets leave the politricksters outta this:icon_smile:


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## BoneMan1000

sMACkaddict said:
			
		

> Haha lets leave the politricksters outta this:icon_smile:


 
Not only have I been slapped on the wrist but I've been censored too. :angrywife: 

And all I did was state a fact. 

Lesson learned though.


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## NorCalHal

I have a lumen counter. After reading this thread I checked yesterday my lights. I took a reading with the blower on, and off. No difference what so ever.
My 2 cents.


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## Roddy

*The negatives are that the glass in the hood can cut the lumen output by up to 10%,*

Is there any truth to this part of that statement??


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## pcduck

> The negatives are that the glass in the hood can cut the lumen output by up to 10%,



I did a little research on this and the info I gathered stated a 2 to 4% loss per surface area. There are 2 surfaces to a piece of glass so that would be a total loss of 4 to 8%.  These percentages are from an bare bulb set perpendicular  to a piece of glass as it would be in an a/c hood with glass.


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## Roddy

:aok:


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## PartyBro420

Not sure if anyone mentioned it but air cooling a bulb increases the life of the bulb if it's cooled evenly. uneven expansion and contraction from heating and cooling non uniformly decreases the durability of any and everything over time.

IMO and experience it's best to keep anything that gives off heat as cool as possible unless you're talking about a heater or something that is meant to be giving off heat.


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## PartyBro420

pcduck said:
			
		

> I did a little research on this and the info I gathered stated a 2 to 4% loss per surface area. There are 2 surfaces to a piece of glass so that would be a total loss of 4 to 8%.  These percentages are from an bare bulb set perpendicular  to a piece of glass as it would be in an a/c hood with glass.




Also i was thinking about cooltubes... curved glass reflects light differently also which may in turn cause a bit more lumen loss.


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## sMACkaddict

pcduck said:
			
		

> These percentages are from an bare bulb set perpendicular  to a piece of glass as it would be in an a/c hood with glass.


Not trying to be a smartass, but doesbt the light sit parallel?


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## pcduck

sMACkaddict said:
			
		

> Not trying to be a smartass, but doesbt the light sit parallel?



Yes but the light being emitted from the bulb is perpendicular

A line is perpendicular to another if it meets or crosses it at right angles (90°).


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## sMACkaddict

pcduck said:
			
		

> Yes but the light being emitted from the bulb is perpendicular



ahhh, oh k.



			
				pcduck said:
			
		

> A line is perpendicular to another if it meets or crosses it at right angles (90°).



:holysheep: seriously?  wouldn't I have to understand the difference between parallel and perpendicular to even ask my initial question?


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## Kushluvr

OGKushman said:
			
		

> IMHO if I had to do it all over again....4ft parabolics and a mini split




i second that...........co2 of course!


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## pcduck

> seriously? wouldn't I have to understand the difference between parallel and perpendicular to even ask my initial question?



I don't what you understand:confused2:

If one would know the difference why would one ask the question:confused2:


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## sMACkaddict

Can you not see where you were unclear?



			
				pcduck said:
			
		

> These percentages are from an bare bulb set perpendicular  to a piece of glass as it would be in an a/c hood with glass.



I have yet to see a system where, and I quote, "an bare bulb set perpendicular to a piece of glass"

any other confusions?


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## pcduck

sMACkaddict said:
			
		

> Can you not see where you were unclear?
> 
> 
> 
> I have yet to see a system where, and I quote, "an bare bulb set perpendicular to a piece of glass"
> 
> any other confusions?



 I could see where there might be some confusion But since I understood it I just figured anybody could, as we were talking light rays and refectance.  I guess I could have been a bit clearer by saying_ when light perpendicularly strikes the surface_._ As it would in an a/c hood with glass_. Or I could have just added a comma.:confused2:

I don't think you need a system to measure the total reflectance of glass. An incandescent light would work or even the sun.


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## sMACkaddict

got ya, I have lots of temperature difficulties because of my lights housing, its a steel box with a tempered glass window... and I live in a concrete house, so it makes ventilation difficult.... I have AC in the room that the closet is in, but I am using local bag seed currently so I hope the strain is local and acclimatized to higher temps...

sMACk


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