Hey fresheadies, check this link

Answers about CFL, HPS, How Much Light...

It's a sticky in indoor lighting.

A 250 hps puts out around 28,000 lumens, which in your area gives 28,000/8.25=3394 lumens per sq ft. The sticky says 3000 lumens Gives "Pretty Good growth. Enough light for the entire light cycle, although your yields may be lower."

Whereas 5000 lumens per sq ft "Optimal growth. Dense growth in all stages"

He also says "I've seen people use a 250w in a 3' x 3' room and get good results. That's 9 sq. ft. which = 3000 lumens a sq. ft. (Really, a 250w HPS is better in a smaller area.)"

So you can use a 250w but you'll need more if you want optimal lumens for your plants and more importantly optimal yields.


Why will venting out be an issue? You really need to exhaust the heat out of the grow area and allow new fresh air to be brought in. I can't tell you the temperatures the lights get too, only that they both get very hot.