hi...if you want a reference from a beginner who had to work with limited resources:

It sounds like you have ventiliation under control, but I didn't...

In an unheated bedroom, when the outside winter temperature in Northern California was in the 50s and low 60s, it ran anywhere from 78 to 82 degrees a foot or more under my 400w lamp.

When the outside temperature was unusually warm, in the 70s, the closet temperature pushed 90...all depending on how much the doors were cracked.

I had two oscillating fans, one angled over the top of plants and back toward the bulb, and another placed right next to the light, blowing heat away from the unit and back into the bedroom.

2 other possible factors building heat:

I switched to a MH conversion bulb with great results, but more heat
I used an Econogrow Mini with a built-in ballast, so heat was hard to dissipate.

It sounds like your setup should give you lower temperatures than I had.

And, as far as hanging distance, I kept mine 12 - 18 inches above the tops.

"Here's where my future quote will go"
notanotherteensmoker Reviewed by notanotherteensmoker on . HPS 400 sufficient ? ... heat ? I have grown exclusively with Flourescents for many years, 320 watts of 4-footers, because I just never wanted to deal with the heat put out by the sodium lamps ... but, I am thinking of experimenting with a 400-watt sodium at the next flower time ... my cabinet is 2ft x 4ft x 6.5ft ... would a 400w be sufficient , or just barely ? ... also, how much heat will the 400 produce ??, finally, how high above the plants would the 400-watt HPS need to hang ?? ... thanks in advance for answers :smokin: Rating: 5