Just blowing air across the enclosed ducted light fixture at up to 539CFM WILL NOT cool the temperature of the lamp!!!....or the Room.

Don't be mislead!

My experince indicates that even a air cooled fixture will get no cooler that the temperature of the outside air source.

I have a 4x5 x9 room. In North Texas - it's in the 90'-100' outside during the day, right now.

I run a 549 CFM exhaust - drawing thru the 6" ducted air cooled fixture which is drawing the outside air from under the house crawl space.

Additionally -I'm running a small 5ton A/C unit at 78'. - Only fresh air is when I open the door.

I'm burning a 1000 HPS and I can adjust the light to any height in the room and adjust the room temps by 74' - 90' and have never seen over 90'

A 1000HPS puts off 3,200 BTU

It took three different air flow duct layouts to achieve this atmosphere. Drawing the outside air from an intake at the shingled roof area -was sending air temperature 94' to the light fixture and I couldn't get the room below 94'.

I got rid of the outside air FEED into the room and changed my Light fixture outside air source to 20' cooler from under the house.