400w HPS heat and ventilation question.

I was wondering what kind of temps I would be looking at with the following setup. I plan on using a 117 CFM inline fan and the heat shield for my reflector and maybe some insulated duct work.

I will be venting just the light and don't plan on having any other ventilation for the room so my c02 doesn't go to waste.

I've read that plants can hold up to 90f with 1500 ppm c02 levels. The closet is 1.5x4x6. I will be growing White Rhino if that matters. Anyway here is the setup.

Fantech FX4 Centrifugal Fan - 117 cfm
Fantech FX4 Centrifugal Fan - 117 cfm |

Sun Shield™ Reflector & Ducting Heat Shield $65
SUN SHIELD FOR SUPER SUN 2 [904480] - Fans, Blowers & Ducting - Environmental Controllers, CO2 Generators, Fans, Blowers & Duct, Air Purification - HorticultureSource.com

Super Sun 2 Reflector $119
Super Sun 2 - 6 Inch Air-Cooled Reflector - Free Shipping!

430 HPS Hortilux Bulb $92
430 HPS Hortilux Bulb - 58,500 lumens |

Are you running the light on a closed loop (drawing air from outside your closet, running throught the light and the back outside closet) or an open loop (drawing air from the closet, through the light, and then outside closet)?

I'm assuming that since you are adding co2 that you would be using a closed loop design. That being the case it probably will depend on the temeprature of the air that you are using to cool the light. If you are adding some a/c fresh air to the closet and if the air that you are using to cool the light is below 75 degrees then you shouldn't have any problem at all.

If you have heat problems I would suggest an open loop cooling design. This way you are constantly supplying fresh air conditioned air (keep in mind that you must have a properly sized air intake to create good airflow) . If using this design you will have no heat issues, but on the downside you will not have the advantage of the co2 (since it will be exausted out).

Don't skimp on the reflector heat shield, worth every penny.

Trust me when I say that its better to have lower temperatures and low co2 than high tempertures with high co2. Yes plants will grow in 90 degree heat but that stress reduces productivity.

If it were me I would use a 600 watt water-cooled fixture and seal the closet completely. Used with a 1/4 hp chiller it will cool the light and will actually cool the closet some at the same time.