# 8" Air Cooled Refector Hoods  Which one?



## CountryBoy (Apr 18, 2012)

I was looking to purchase a sun systems Magnum xxxl 8" reflector hood then I came across HTG's Big Daddy 3'x3' 8". 
Does anyone know if the quality is the same or close.
Thanks in advance if any info.

CB :icon_smile:


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## bwanabud (Apr 18, 2012)

Unless you're planning to install a lot of lites, ducted together.....the 6" Vortex fans pull about 450ish CFM, so the 8" flange isn't usually needed.


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## CountryBoy (Apr 18, 2012)

2 1000's to start with that is why I am considering 8" cooling.
CB:icon_smile:


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## bwanabud (Apr 18, 2012)

heres some venting info

Step 1 &#8211; Room Volume
First the volume of the room needs to be calculated. To calculate multiply length x width x height of growing area e.g. A room that is 8' x 8' x 8' will have a volume of 512 cubic feet. 


Step 2 &#8211; CFM Required
The fan should be able to adequately exchange the air in a grow room once every three minutes. Therefore, 512 cubic feet/3 minutes = 171 cfm. This will be the absolute minimum cfm for exchanging the air in a grow room.


Step 3 &#8211; Additional factors
Unfortunately, the minimum cfm needed to ventilate a grow room is never quite that simple. Once the grower has calculated the minimum cfm required for their grow room the following additional factors need to be considered:

Number of HID lights &#8211; add 5% per air cooled light or 10-15% per non-air cooled light. 


CO2 &#8211; add 5% for rooms with CO2 enrichment 


Filters &#8211; if a carbon filter is to be used with the exhaust system then add 20%


Ambient temperature &#8211; for hot climates (such as Southern California) add 25%, for hot and humid climates (such as Florida) add up to 40%.


And some more if you need it 
xxx.bghydro.com/BGH/static/articles/0706_vent2.asp


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## CountryBoy (Apr 18, 2012)

bwanabud that is some of the best info I have seen on here.
Thanks for the info and for being easy to communicate with. Not all grow replyers are able to do that.

CB:icon_smile:


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## bwanabud (Apr 18, 2012)

My pleasure CB, tons of great people here...willing to help out


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## PartyBro420 (Apr 18, 2012)

I really don't like that system for working out what type of fan you need, because there is no way that the minimum cfm required for a space that size will adequately vent the space with even the extra 5%'s etc added on for a hood and filter. Nor will it cool a light.

Giving people information like this in my opinion just confuses a lot of the time. I had the same instruction showed to me and it really just succeeded in showing me a good way to run a lighting system in parallel...

I also don't agree that adding less cfm in addition when adding an a/c hood over an open hood makes sense. The closed hood will cause more pressure, lowering the efficiency of the fan connected to it, whereas the open hood can be cooled with a simple fan, blowing heated air upwards towards the exhaust to begin with.

I suppose knowing the bare minimum you need is good, but if it's not aiding you in your choice of fans then what good does it do to know? To my knowledge pretty much everyone here buys good centrifugal fans. I had a huge conversation in my journal about fans and their capabilities. So why bother instructing someone that roughly 275 cfm for a 512cf space would be adequate?

Based on what i've seen and experienced and read from other folks instruction here, is that you're better off with a bigger fan. You can control it's speed and cfm output, and if you ever get a bigger space you won't have to replace the fan.

I run 2 1kw lights as well with one 8" stealth centrifugal at 745 cfm. My room is just under 500 SF and the temp EVEN WITH THIS HUGE FAN can still get up towards 80.


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## bwanabud (Apr 18, 2012)

I don't agree with the open hood light design....unless you live in an area with hi temps all year. The Cooled hoods work much better IMHO.

You have the ability to cool them much easier, with less CFM. The larger fan theory, I agree with. A fan control can slow it down for your needs, crank it up(when hot, or more fans are added)when you want.

The amount of ventilation for an area has many variables....lites, BTU's created, oxogen needs, plant obstruction, etc...each grower has to find the "magic" formula. 

The specs provided by the light mfg. are just guidelines..always lean to the high side for adjustability.


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## Skool (Apr 18, 2012)

bwanabud said:
			
		

> I don't agree with the open hood light design....unless you live in an area with hi temps all year. The Cooled hoods work much better IMHO.
> 
> You have the ability to cool them much easier, with less CFM. The larger fan theory, I agree with. A fan control can slow it down for your needs, crank it up(when hot, or more fans are added)when you want.
> 
> ...


 
Can the air be pulled through to fast?


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## bwanabud (Apr 18, 2012)

Skool said:
			
		

> Can the air be pulled through to fast?


 
Technically speaking, yes....if your ambient air is cooled, and high CFM is pushed past the bulb, it would/could significantly cool the bulb and lower Lumen output. But, that would be rare..unless you're pulling 800 CFM thru 1 lite


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## DiamondJim420 (Apr 26, 2012)

I really like my Luxor vertical-bulb hood with 8" flanges...throws an awesome light pattern, and is surprisingly easy to keep cool.


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## Hushpuppy (Apr 26, 2012)

Where did you get that vertical light fixture DJ? I have never seen one like that. What kind of footprint does it throw?


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## DiamondJim420 (Apr 26, 2012)

Hushpuppy said:
			
		

> Where did you get that vertical light fixture DJ? I have never seen one like that. What kind of footprint does it throw?


 
I got mine from hXXp://www.growlightsupply.com/index.php?main_page=product_info&products_id=411

It throws an awesome footprint.  But it's a BEAST.  Very heavy and bulky.  So heavy that I (probably due to paranoia) have TWO ratchet straps on EACH side to hang it from.

The thing that jumps out to me is how easy it is to keep cool.  It's design is supposed to be one that greatly helps reduce heat.  I don't know if it's because of design or because of my "overkill" 636 CFM fan, but the room stays 70-75 degrees F all the time.  I'm actually thinking of trying a 1000-watt bulb in there...


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## Raef1 (Feb 18, 2013)

DiamondJim420 said:
			
		

> I got mine from hXXp://www.growlightsupply.com/index.php?main_page=product_info&products_id=411
> 
> It throws an awesome footprint.  But it's a BEAST.  Very heavy and bulky.  So heavy that I (probably due to paranoia) have TWO ratchet straps on EACH side to hang it from.
> 
> The thing that jumps out to me is how easy it is to keep cool.  It's design is supposed to be one that greatly helps reduce heat.  I don't know if it's because of design or because of my "overkill" 636 CFM fan, but the room stays 70-75 degrees F all the time.  I'm actually thinking of trying a 1000-watt bulb in there...


   this is a year old, did you put the 1000w in and if so how did it work?  i only have 7 feet in height, but i scrog, is there enough room for a luxor, it is tall reflector, thanks


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## Hushpuppy (Feb 19, 2013)

Hey Raef, I personally wouldn't use that particular light. I don't like the angles of the reflector walls. I have 6 of these here and absolutely love them. I nearly have to put on sun glasses when I work under them. They take a little bit of assembly of the reflector but its no problem. The light footprint on them is great and they stay very cool. The company is also very reliable for getting stuff shipped to you in a reasonable time. Copy the url into your browser then change the hxxp to http before hitting enter or it will mis direct you. 

hxxp://www.hpsgrowlightstore.com/hps1510/best-grow-light-systems/600-watt-grow-light-sets/ipower-grow-light-600w-hps-mh-dimmable-cool-tube-xxl-set.html


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## WeedHopper (Feb 19, 2013)

I always like Negative air preasure in my growroom.


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## Hushpuppy (Feb 19, 2013)

me too


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## ShOrTbUs (Feb 19, 2013)

agreed, negative air pressure is great for deterring airborne pests


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## WeedHopper (Feb 19, 2013)

Thats a nice light system Hushpuppy.


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## Hushpuppy (Feb 20, 2013)

Yeah I like them. They work quite well. I have had several for over a year now without issues, so when I expanded, I continued to order them. The only thing I would add to those is the "Digilux" bulbs. I bought some of those as backups to the Ipower bulbs and they are considerably brighter and have more blue light in the spectrum, and they are not overly expensive like the Hortilux.


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