I'm in the process of deciding on a lighting system for my grow process. I was thinking flourescents for veg period and then using a HPS to finish them. I then realized I could just buy a HPS setup and put a MH bulb in for the beginning. I've read alot on how HPS can create to much heat but because I've never used one, I'm not sure what to expect. The closet that it would be in is about 4.5x8 and the grow space for the primary plants will be 3x3. Without an exhaust system will this create to much heat for my space? The walls are flat white and the light I planned on hanging off the top shelf in the closet.
Will you be leaving the closet door closed at all times? If so then I'd say you're going to run into some heat issues, but still might be able to pull it off. I'm using a 400w mh/hps in a closet that's 2'x2'x10'. Sometimes with the door closed it'll get into the high 90s (obviously not ideal). With the door open however it stays around low 80s which is "ok". They definitely do give off a lot of heat.
Grow space sounds ok for HPS/MH but yes you must, must have ventilation. Have you chosen a strain or is it bagseed? You will need a decent desktop fan (just my opinion, others use PC fans, but I wonder about the efficiency with the heat of HPS). A carbon scrubber with an in-line extractor fan is something you should have too. An exchange of air and movement of air is very important....it's not just about heat. So, soil or hydro? There are a lot of CFL fans on here, and they do very well with their grows. But if you're going to use HPS for flowering you're going to have to deal with the heat issues at some point so it might as well be straight away. The MH is a little hotter, so if you can keep the heat to a resonable level with MH, the HPS will be fine. I just switched and my temps are much more managable now.
Are you in flower yet? If you try to flower in the 90's you're going to have no bud growth. I have a 400mh and a 400hps that would heat a whole bedroom to the low 90's if I had the door shut. The only way I ended up solving that was A/C.
Im still at the beginning veg state. With enough CFL would I be capable of the same grow i'd obtain with a 400w hps?
I have a 400 watt hps in a closet and have the smae problem i even have an attic that i've tried to vent into and then switched it to the fresh air supply and still have heat issues. Im now debating between getting and aircool tube(possibly thinking about switching to a stadium style grow) or downgrading to a 250, honestly i'm thinking of doing booth get a 250 watt hps and the tube, and then just supplemnting with fouros. The 400watt just generates so much heat you need somewhere to dissipate it and unfotunately dissipating into a closet that is where you get your fresh intake is a problem. The other option you have is say fuck spending alot of money on vent systems and by those little ac units that are not the ones that goe in the window.(you will probably need a dehumidifier aswell especially if going hydro). Honestly 400w hps in closets do not work out so well, your better of getting a 250 or even a 150 supplement with flouros for better spectrum and just run al the lights all the time. Even with a 150 and 75-100 cfl you will run into heat problems on extremely hot days.