canopy fan

[horsefarm5]

I'm building a canopy and it will house 2- 175 watt se bulbs and 2 110 vho. My question is I have a 4 1/2 inch fan and was wondering if the fan should blow across the bulbs or use it to expel heat...I also have 2 computer fans, should I incorporate these into the design? Any help and ideas are appreciated
Thanks
Mike

[gh0st]

I always mount them blowing into the canopy as long as it isn't sealed up and airtight. Forcing air in will have less moisture going through the fans and should extend their lifespan.

It also is much more effective at lowering temps.

I tried my last fans blowing both in and out. Blowing in was three degrees cooler than out.

[horsefarm5]

Thanks for the reply

[nozleman]

Yes I have built two canopies, they should blow in! And I would add at least two, for safety and incase one goes out!

[carlisimo1969]

I put a 4" hole above each halide fixture and have fans blowing into the canopy, heat directly vents out the top and everything stays cool.

[AZDesertRat]

Mine is pretty much like carlisimos. Two 4" Vantec Stealth fans, one in each end blowing in with equal sized or larger holes in the canopy roof over the reflectors for heat to escape. This also takes advantage of convection, I get heat rising out even when the fans are off just by natural convection.