Start up cost? Yes. Long term cost? No. Figure you buy 3 6 light t-5s for the flower room. That will cost you like 600+ just for the fixtures. Then you need to go out and buy different bulbs and replace those bulbs about every 4 grows. You can buy 2 led fixtures to cover that space for like 1200 and don't have to worry about buying bulbs. On top of that your electric bill will be lower and it will be easier to work around two lights than 3 fixtures that equal the same dimensions as your grow room.
Shilling for LEDs in the "Club T5" thread? Whatever.
T5 are meant for growing shorter bushier plants or SOG or SCROG. The lamps don't penetrate like LED or HID. The light is spread out more evenly over a 2' x 4' area instead, assuming an 8 lamp 4 foot fixture. You could use side lighting to help grow taller plants, if you want, otherwise, keeping your plants short, topped several times, and well pruned is key to getting good yields using T5. Keep the lamp a few inches above the tops and raise the fixture as the tops grow into it. This keeps the tops of the buds elongating with enough light to keep the lower parts of the buds maturing and filling in.
As far as the number and type of fixtures, it's all relevant to your growing style and area/room(s). Frankly I don't know much about the new LED lamps available, I have an older 5 spectrum UFO that sucks ass... I don't care for the visible light spectrum it casts. It's purple. Purple light makes it hard to monitor your girls health, imo. Plus, LEDs will bleach your plants if they're too close, so you have height issues to deal with. And LEDs still cost too much, initially. If the LED were the type of super bright white light they're using in street lamps now, then that would be something to consider. The spectrum might not be perfect, but that amount of intensity would make up for it, especially if you could get a couple of different types, say a 3000k for flower and a 6000k for grow.
You can get an case (25) of good quality of T5 bulbs for under $120 on Ebay. Also, most fixtures come with your choice of grow or bloom bulbs to start you out. You can mix and match the light spectrum with some some of the specialty bulbs if you choose. And like LED, heat is easier to control with T5 than HID.
IDK, shelling out $1200 up front for LEDs vs. $600 for T5? Lets see:
$600 for 3 8 bulb fixtures w/lamps + a case of 25 T5 lamps per year at $120, all from Ebay = $1200 over 7 years.
It would take 7 years to before the T5 becomes more expensive than a pair of LED fixtures.
The drawback would be the buds from a T5 likely won't be as dense as from HID, and probably less dense than LED. But that's almost as much dependent on strain and growing style.
My first grow several years ago netted 6 oz. from a single 6 lamp 324w T5. 4 plants less than 3 ft tall (including container) in a 2.5' x 5' grow closet. If you're good, you could probably pull 16 oz./month using the three fixture set up above in a perpetual grow op.
