hey cartman, you seen very knowledgeable about HVAC systems and they have been giving me fits the past couple weeks trying to figure my new ventillation system out...

I am upgrading my medical grow and have some questions on my new design.

I am planning on having 3 rows with each row having 9 1000w XXXL air cooled reflectors. each row will be 4ft wide and 36ft long. There will be a space of 3ft between each row so that the plants are each to access. I live in the north west USA so during the summers it can get up to 100 and the winters get down below zero at times. I am planning on having the intake for my lights to be pulling air from the crawl space and exhausting it outside or back into the house during the winter to help with heating. I'm sure that pulling air from the crawl space (which is 4ft tall with 1360 square feet) I will need to have an intake fan for the crawl space/basement to help create a positive pressure. I will also be pulling air across the lights compared to pushing it since it is more efficient.

My Questions:
How many reflectors can I hook up in a row? I can't imagine I could hook up all 9 in a row with each flowing into each other cause after the 2nd or 3rd light wouldn't the air be so hot it wouldn't be cooling the lights?

What size fan will I need to use to cool the lights? I've read that I should have around 250-350cfm per light but is that right?

I know that the 6" hoods allow for more light to be reflected to the plants but the 8" would give me better air flow. so which should i eventually decide on?


would this work? have my intake be 30x30 box ducting coming from crawl space, then split into 3 14" intake trunks that run the length of my rows. (I will also have to hook up a 6" or 8" to the main intake for my 4 lights in the veg). Each HPS light will have 6" or 8" flex insulated tubing (i could probably do 6" if i'm doing this method) coming from the intake 14" trunk to the HPS light then to the 14" insulated exhaust trunk for each row of lights then at the end of each exhaust row trunk I could have a 14" canfan 1823cfm fan ($520) or 14" vortex fan 2900cfm ($1000). Each insulated exhaust trunk would directly connect after the fan run into a 20x20 insulted box duct that runs into the attic. does this sound like the best way to run the system? i've done by homework but i cant find a ton of information on this topic or maybe i've just been looking in the wrong spot ha!
tubularty Reviewed by tubularty on . Air-cooled hood...can you pull too much air through? I just picked up an enclosed reflector with 6" air-cooling flanges. I just ordered a 6" inline fan that is rated to 200 CFM, but it looks like it only runs at 160 CFM. I don't think that'll be enough for my 1000W HPS. My other option was a 424 CFM fan!! That air would be fuckin roaring through the hood! If my nerd calcs are right (Q=VA), then the air would theoretically be coming through the hood at 36 ft/s (25mph). That's a pretty heavy gale. Could that be harmful to the electronics Rating: 5