Setup help please

I'm a first time grower, and I'm working with a space aprox. 3.5 x3.5 and just under 7' ceiling.

I understand I'll need intake and exhaust ventilation and I'm working that out now. I'm getting ready to order a hps light and need to know how much light I can get away with in this space, without causing excessive heat. I would like to try and avoid using cooltube reflectors if possible to keep costs down. Can I get away with using a 600 watt light? Or would a 400 watt be more appropriate?

Really appreciate you helping a new grower out, I'll be watching for your advice.

Thanks

BB

using a 600w without a cooltube will cause a lot of heat. depending on the place you live and how hot it is out there you will need to match up an out-take fan.
I live in a hot place - right now its about 27C outside, and thats chilli, so I'd need at least a 650CMPH fan, and keeping the lights pretty high above the trees.
however, with a cool tube I could have used a little smaller fan and place the light much closer, resulting in way more yield and growth rate.

In your kind of space I think a 400w is enough.

You can alway try to improvise a cool-tube, there are numerous DIY instructables. I find it VERY important.

If you live in a place where it is around 22C at this times I think a 320CMPH will do with a cooltube and a 400w.
can't find any CubicMeterPerHour to CFM calculator, sorry.

Thanks for the help.

Being new at this makes it kinda tough to know how much heat these hps lamps will produce.

bb