Push air or pull through the lights?

Ive always thought it was better to have the fan near the exhaust pulling the air through the lights, but my friend thinks it should be the exact opposite placing the fan near the intake. Say one was going to put 4 1000's in a 15ft x 15ft room and use 1 8inch 750 cfm inline fan per 2 1000's. Using 6inch ducting and connections on the hoods with reducers on the fans and pulling air from outside the room and exhausting outside. Where would be best place for the fan for cooling the lights and the room? Near the intake or exhaust? Thanks for any opinions. Ill try to run tests later to confirm results.

pull...works for me.

You have better results putting it at the exhaust end since negative pressure is working with you, rather than backpressure working against you. Some situations require putting the fan on the intake but you have to use a larger fan to achieve the same results.

Pulling air is more efficient.

Pulling air is definitely the way to do it.

The important variable here is heat. If you are exhausting through a couple of 1000 watt MH hoods that air is going to be very, very hot. The operational temperature range for CAN-FAN's is stated on the unit itself or with the accompanying literature. Now while this temperature is the stated static air temperature and not the input temperature, pulling super heated air through the fan will heat it up and may lead to premature failure.

pallaromp said:

The important variable here is heat. If you are exhausting through a couple of 1000 watt MH hoods that air is going to be very, very hot. The operational temperature range for CAN-FAN's is stated on the unit itself or with the accompanying literature. Now while this temperature is the stated static air temperature and not the input temperature, pulling super heated air through the fan will heat it up and may lead to premature failure.

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ah.that makes sense, but iv'e been pulling air with the same fan for years 8+...maybe i'll push it now.

I was told that pulling is best but if you do push have two holes for better circulation

pallaromp said:

The important variable here is heat. If you are exhausting through a couple of 1000 watt MH hoods that air is going to be very, very hot. The operational temperature range for CAN-FAN's is stated on the unit itself or with the accompanying literature. Now while this temperature is the stated static air temperature and not the input temperature, pulling super heated air through the fan will heat it up and may lead to premature failure.

Click to expand...

Depends on the CFM of your fan. If your fan is sufficient the air will never be hot because it does not have a long enough time near the light to become heated.

i just went through that problem and its better on the exhaust end