I'm afraid that $10,000 number is much too conservative. 1000W lighting setups alone are the most expensive among the venting and the etc's.
A 1000W light/hood/ballast runs anywhere between 300-500 bucks depending on the manufacturer and quality, and they only cover a MAX 7x7 ft (49 sq. ft.) area and that's pushing the limit. I say MAX because multiple lights help create an overlap. Just one stand-alone light covers about 6x6 ft. and that's also pushing the limits.
21000 sq. ft divided by 49 sq. ft = 428.59 1000W lights
429 1000W lights x $300 (low-balling for retail buys) = $128,571
There is a way to fully DIY the wire-ups of 1000W lights for cheaper if the grower is so inclined to deal with that headache, but it would only cut the cost in half at absolute best but more likely only by 1/3. (Even just a top of the line HPS bulb can run in the $100-$200 range!)
$128K with 1/3 of the cost cut out is $90K.
Now factor in the ventilation costs. Whether they are daisy-chaining the duct-work from light hood to light hood, or if the lights are just exposed bulbs with basic reflectors... that's another thing to consider. (Enclosed lights are better IMO b/c if a bulb explodes for any reason, there's a whole new sh!tshow to deal with.)
Also... is it a soil or hydro grow op? There's also the costs of grow mediums, nutrients, seeds, insect pest control, and multiple other etc.'s. Even all the way down to paying manual labor trimmers to harvest the buds.
There are many cost factors to consider in growing and I won't bore you with the math, but $10K for 21000 sq. ft is waaaay to low.
I'm a CO grower and have been for 9 years. The rule of thumb for growing is... Whatever you think you're budget is going to be, you are probably wrong. Unless it's an outdoor grow but that's got its own headaches too.
Have a great weekend! Go CGRA!
