Air cooled reflectors and loss of lumens?

I putting together a shopping list for a set up in a grow tent. With a air cooled reflector that has the round vents on either end are lumens being lost out end of the reflector, going out the intake and exhaust tubing? If so how much light is lost? Looking at the Super Sun horizontal reflector. The design seems like a good choice to send maximum light to the garden area.

No..you don't lose any lumens at all. Lumens measure brightness of light and as long as it's reflected in a direction then you will maintain all lumens.

Well since air cooled lights cool the radiant heat coming off of the bulb it'd make sense that it could then get closer to the plants without burning them. And since lumens decrease the further away from the plant you go it would actually give you MORE lumens if you could get closer, which an air cooled reflector or cooltube will allow for.

Reflectors actually do diminish lumen output. Some far more than others, there was s good forum that tested the different hoods and their efficiency. But basically when the hood reflects light it loses light there in three ways: one the surface itself isn't 100% reflective, so some is absorbed. two not all the light is reflected in the right way, some of the light gets reflected back into the bulb which means passing through it again and two layers of glass. Three reflected light travels further to get to the plant, so applying the inverse square principal you lose light. If the hood is air cooled you lose about 10% from the glass, but you make up by closing the distance to the plants.

So with a hood on a horizontal setup you gain tons of usable light and effectively increase the lumens your plants get by a very large percent, I would sat 40% at least. But you do lose lumens technically. The only way to not lose lumens is to grow vertically, but then keep in mind each plant is getting less light(though generally more usable) due to it not being focused.

what the two said...you were prob thinking that you lost lumens due the the glass,but no..you dont...get that sumbitch closer and they will thank you later

karr does prove a point,but he said it him self..you make up by getting them closer..so in the long run,how can you loose..you fight the heat and get more light due to the sealed beam..you always loose lil light wich ever is that your trying to do,light doesnt take orserd on wich direction to roll ,all you can do is adapt and carry on

Yes be careful!!! If you use a fan too strong for the light it will suck all the lumens out of the bulb and blow them out the other end.

probably the most important factor to determine which to get is HEAT. I use a open reflector and have a big a/c to remove the heat.
In exchange, I have no intakes or exhaust and I run c02. With an air cooled hood, you have ducting running everywhere, exhaust fans to quiet, smell to cover and heat that you need to dispose of .

VICTORYGARDENSHYDRO said:

probably the most important factor to determine which to get is HEAT. I use a open reflector and have a big a/c to remove the heat.
In exchange, I have no intakes or exhaust and I run c02. With an air cooled hood, you have ducting running everywhere, exhaust fans to quiet, smell to cover and heat that you need to dispose of .

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with an open reflector ie batwing style one- whats the best way to cool a 400w hps in a 40x40x78 tent ?

^Cooltube......

I use open air reflectors and get nice tight dense buds. If you run a cool tube close to the plants granted there is more light penetration but the light dispersion angle suffers and you loose coverage.

There should be a study done on how much plant loss you see between the two. Like a light penetration vs footprint. Like say you lost a collective 2 sq ft of footprint but gained a lot more lumens deeper. I wonder how much it would differ.

bigv1976 said:

Yes be careful!!! If you use a fan too strong for the light it will suck all the lumens out of the bulb and blow them out the other end.

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Lol if the fan were a black hole yes you will have 0 lumens

in addition bulbs are meant to run at certain temps. when cool air is passing over a bulb it is not performing at its optimum level. there is lots of reactions going on within the bulb and certain level of heat are necessary for all these reactions to happen. cooling a bulb to much can change the spectrum of the bulb because these reactions are not taking place. gavita is considered the elite in horticulture lighting and there hoods are not vented because they optimize the bulbs performance by not cooling them. i just recently bought a luxor hood. it is vented but removes heat by convection so the bulb stays fairly hot. air is not circulating directly over the bulb. instead heat rises into a chamber and the fan removes the heat from this chamber. the venting cools but not as good as other hoods. the advantage is that the bulb is running properly with some heat removal. the luxor hood is a beast. it pumps light down like no other hood i have used

the colour temperature of light (in hps and mh) is controlled by passing a current through a filament I sincerely doubt that an inline fan would take away any/enough heat from the inside of the glass tube the filament is in let alone the filament to damage performance, they just remove heat from around the outside of the bulb which doesn't affect the 'reaction' within the bulb (and filament) in the slightest (except for maybe the 2-5 lumens or however many lost from passing through the glass tube).

Though I suppose your statement could hold true for bulbs like CFL's, Fluoro tubes and Plasma Lights where the colour is controlled by passing a current through particular gasses/powders or whatever, though I still don't think an inline fan would make the slightest bit of difference to the 'reactions' and therefor the performance of these lights either.

and putting down light is mainly enhanced by the shape/texture of the reflective hood not temperature.

Sorry if that was a bit rude but I don't think the inline fan in a cooltube would make that much if any difference except in room temps unless you live in a ridiculously cold area, in which case you probably wouldn't need a cooltube in the 1st place

i disagree with you matchbox. i had allot of inquires with the makers of the luxor hood before i purchased it. it was actually designed to help extend bulb life and maximize spectrum thus it is designed to remove heat by convection and not with direct flow over it. the makers of the luxor consider it there top of the line reflector and most advanced one they have ever built. there was lots of tests done on actual spectral analysis of the bulb over there other models. it proved to produce more lumens and more conformed spectral mixing. in other words the hood made the bulb more efficient. i can attest after one grow with it that its deffinately not like any other hood on the market. it pounds light down and literaly has no hot spots. in addition it covers a 4x4 area more uniform then the daystar i had previously. gavita has also been performing these types of tests for years and thats why they dont make an air cooled hood. gavita wants the bulb to perform its best.

Fair enough. I would have just figured the reason they don't do an air cooled hood is because its not as easy/effective to build a sealed hood that reflects as well as an unsealed one.

I just had reservations about the temperature thing.