air to cold for my hood?

mountainboy

Well-Known Member
Hi, this is my first 1000w hps, I have an air cooled hood with 8inch ducts, and a 400cfm fan. I was going to draw air from outside to cool my light,but it is sometimes way below 0 deg in the winter months, and I'm worried I'll get condensation and blow the bulb up. could this happen?
 

thatguy1122

Member
your gnna have to pull it in sumwere from inside your house cause think about how cold itll get with the lights off an im sure that constant super heating an cooling cant be good for your light bulbs but you wont have to woory bout the lights cause your plants will b dead from frost lol
 

mrmadcow

Well-Known Member
you are talking about pulling air from outside through the light fixture & back out of the grow room,right? I will also assume the fan will be off when the light goes out. should not be a problem, they use large HPS lights for streetlights, right? they may not use fans but the ones I have seen have vents in the top & open bottoms so when heat rises out the top, it sucks in cold air from the bottom.
 

legallyflying

Well-Known Member
That is a no no. It won't hurt your bulb at all, in fact it will run nice and cool. The problem is going to be that it will be raining from your ducting and hood. You can use outside air to reduce the air temp getting sucked into your ducting but don't directly plumb it.

I have a 8" flex duct that is connected to an outside window. I then cut it in half. In the summer when it's 50 outside I tape the duct together and it's not an issue, nice cool air. In the winter, when really cold air will cause condensation, I just clamp each end of the duct to a little piece of wood with about an 18" gap in between. So when the fan is running im taking some 70 degree basement air and some really cold air from the window duct. If I get condensation, I simply increase the distance or stick an old shirt in the inlet duct.

You have to play with it a bit but you do end up reducing room cooling costs. The magic temp with no condensate (with an 83 degree, 40% humidity flower room) is about 50.
 
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