Ive just finished building a new grow room, as I expand my space, I feel like I should finally make the switch from flouros to HPS. My new room is 8x4 and about 6 foot fall. The ventilation I currently have rigged is a 240cfm intake, and another 240cfm outake. I don't think heat should be an issue and I will only use this room during the colder months anyway. Soooo does anyone have any idea what kind of HPS system would be right for me?, I was thinking 2 400watters or maybe even 2 600watters.... Any brand/model recommendations?
Based on only using the room during colder months, it sounds like you grow outdoors otherwise. It really depends on whether you're seeking to create more of a perpetual setup with mothers and clones or running one-off crops from seed as to how the room will be used as a whole. Off hand, if you're just looking for an even and adequate blanket of HPS lumen intensity I'd certainly go with 2 600w over 400w lights. (2 1000w HPS would be ideal since you have adequate ventilation. BTW, plants veg just fine under under HPS and a MH isn't gospel). While if you're planing on having plants at various stages you could save electricity, though would harvest fewer plants, if the room were divided with a light tight partition where about a third or slightly more of the room housed mamma and/or vegging plants, clones or seedlings. And the other with then just 2 400w (could use the 2 600w) HPS on 12/12 to flower out the plants. The only thing I'm more certain about brand wise is Lumatek isn't really worth the hype and price. Reports are that they often have problems after just a few months of use. Just go with digital ballasts if you can. They are becoming more popular and have been dropping in price lately. Virtual Sun out of Max Tool in So Cal, which gets good reviews sells a 1000w switchable and dimable kit online for $279 if I recall that comes with a remote digital ballast, good timer, fixture w/winged hood, 2 adj fixture mounts and both a HPS and MH bulb and free shipping anywhere in the US. At the 1100w setting on the ballast it kicks out 10% higher lumens, at the cost of a shorter bulb life though.