I started black widow on a 2ft florescent grow light. Now at this stage I purchased a LED light that is equivalent to 600w HPS to use in a 4x4x78" grow tent. How do I vent and calculate heat output of light? Recycle air or get rid of it?
Use a fan and carbon filter. I would go with a 6" fan and a 6" carbon filter. You can find them for a decent price on amazon.
Thanks, I assume carbon so the smell is at a minimum.
Filters help keep the smells down. And, if that is important, it a good thing to have them. If smell is not a problem…no need.
Plenty of affordable fans on the internet…might also consider a speed control for your fan. Makes for best air flow control.
You usually need to vent from the top, to pull the heat out. 600 watts of LED heat the tent air just the same as 600 watts of HPS. Watts are watts. LEDs just make a tiny percentage less heat because they make more light. (Assuming you get good LEDs.)
1BigFella is right. Heat rises…best to vent at high point.