Do Air Cooled Reflectors Work?

It might sound like a stupid question but I'm a bit skeptical when it comes to the effectiveness of air cooled hoods.

My thinking is that most of the heat generated by a HPS bulb SEEMS to be radiant heat as opposed to convection heat.

http://en.wikipedia.org/wiki/Heat#Heat_transfer_in_engineering

If I'm correct, it makes sense that little heat would be removed by an air cooled hood. If you hold your hand under one of these reflectors, you still feel heat through the glass. If you put your hand on top of an aluminum reflector, you don't. That is because aluminum blocks radiant heat.

So, I'm wondering if there is anyone out there who has an air cooled hood but still requires additional venting or if the hoods do make a significant difference.

Air cooled hoods are amazing i got mine and im glad i did my temps dropped from 29c to 24c as soon as i got it installed check out my sig for pics of it

yes they work

yes, i have a cool tube... it doesn't stop stuff from getting hot, but drawing the air into a different room is critical...

yes. they work well

i have 2 1000 watt hooked together with 6 inch flex ducting and a blower drawing outside air in and through the lights and back outside. my room is 6x10 and this system lowers the temp about 18 degrees f. in the summer i still have to use an air conditioner but only for a couple months the rest of the time it stays between 80 and 85 in there. hope that helps

If connected right AND used efficiently, you'll love it !
They aren't needed though.
PLENTY of growers, especially vets, don't bother if the rest of the room is dialed in.
Meaning mainly intake and extraction.
I don't use my Sun System Yield Master II 6" hood's glass lens and my ambients stay 79F - 81F on avg, and 83F in Summer.

Rick

Yes, they work, much of the radiant heat is held in by the metals of the hood itself that is directing more than half of the light downward. The Glass itself absorbs some radiant heat. This plus the conventional heat is leached by the influx of air. Now, the air should be exhausted or the room can be sealed off from the air cooling for maximum efficiency. You also need a sufficient amount, such as 1 6" Inline (Not duct booster) fan per 2x 1000Watt lights, you can get 3-4 1000Watt lights off of a 8" fan/ducting, etc...

I forgot to make one distinction.

I am talking about a loop that is completely isolated from the room air. That is to say that both inlet hose and outlet hose pass outside air only and do not remove any air from inside the grow room. Air enters through a hose, goes through your fixtures and back out never mixing with room air.

Is this how you guys have them set up or is air from the grow room drawn through the lights?

i have my filter in my room running through my light and out my room. passive intake. works fine

RickWhite said:

I forgot to make one distinction.

I am talking about a loop that is completely isolated from the room air. That is to say that both inlet hose and outlet hose pass outside air only and do not remove any air from inside the grow room. Air enters through a hose, goes through your fixtures and back out never mixing with room air.

Is this how you guys have them set up or is air from the grow room drawn through the lights?

Click to expand...

The immediate albedo effect of the environment will absorb light and transfer it to heat - air cooled hoods do nothing to prevent this except that much of the immediate heat - IR does not pass through the glass whereas the visible light does. Additionally and likely more importantly the air cools the hood. Even with 95% reflective aluminum that hood and the glass is absorbing a ton of heat and has a nice large surface area to disperse it with so keeping the hood cool drastically keeps heat out of your enclosure.

/e I use an air cooled hood and its the difference between holding my hand on the glass comfortably or getting burnt - remember that if the glass is hot to my hand it is radiating heat into my tent.

Ive been curious to whether or not id need a air cooled reflector,or if just an aluminum bat wing reflector will be ok for my 250w hps. Im in a cab size of closet. So im subn to this .might learn somthing rt.here!

queenster said:

i have 2 1000 watt hooked together with 6 inch flex ducting and a blower drawing outside air in and through the lights and back outside. my room is 6x10 and this system lowers the temp about 18 degrees f. in the summer i still have to use an air conditioner but only for a couple months the rest of the time it stays between 80 and 85 in there. hope that helps

Click to expand...

do you have an additional exhaust and intake to recycle air or no?

this is a very intresting question to me as I agree with Flo grow post, they are effective and most effective if installed properly (ducting and fan size) but if your room is designed to move air in and out correctly they are not needed , I chose not to use one , because my room has been properly sized for the correct amount of air exchange, so the extra cost is not needed ,the other factor is I feel the glass may diminish the quality and color of the light bulb it self ,I could be wrong but this is my opinion . here is what I made to fit my room 8 inch 24 ga metal round pipe ,open up to 1/2 the radi ,wich give me 16 wide, and cut to a 24 inch lenth, add cables , brackets, 400 mh light fixture and PC fan ........cost to me zip 0

sk8disgruntled said:

i have my filter in my room running through my light and out my room. passive intake. works fine

Click to expand...

Does it still drop your temp?

depends how much you need to drop temps.
I built a dual bulb air-cooled hood.
with 2 400watts inside a 3x3 tent.
I could not run both ballast on "supper lum" and keep temps in check.

also found HPS bulbs made the tent run hotter then with MH

I have now made a aircooled COB light.
so much cooler. I actually have to add a bit of heat this winter