A good amount when I made my cool tube it helped the temps about 10-15%
BukDatAss Reviewed by BukDatAss on . light questions I have a 1000 light in a 4 by 11 room I have the light vented and also an 8000 btu unit in the room but I am still having heat problems, I do not have a glass lens for my reflector, how much heat does the lens keep out of the room if properly vented or exhausted, my fan is 145 bph(or something like that!) Rating: 5