This is my first indoor grow and I am trying to decide between two 150 watt hps lights. The first one is from HGT suppy and the other is a Sun System. The sun system has an internal ballast and I wasn't sure if that would present more heating problems then the HGT supply light (with external ballast) in a 4X2X4 grow box. I would greatly appriciate any help or if you have an opinon on either of these lights. Thanks
Depending on how your gonna fixture the lamp for cooling, I would tell ya to go external ballast. You don't need anything generating more heat then necessary in the box.
I plan on having the exhust on the top and an intake fan near the bottom, but nothing directly cooling the light. So the ballast does put off a decent amount of heat?
You bet the ballast gets warm. For your limited space, I would retink about a air cooled fixture. Cooltube is what I use. If you want to go 21st century check out the water cooled fixtures.
I have been told the exact same thing about the 150w Sun System internal ballast setups from the guys at my hydro shop. They've never steered me wrong either.