Quote Originally Posted by David - WI View Post
I've been struggling to get started on a commercial system for about 5 years.

I have a bunch of four-bulb standard T5 fixtures, so switching to LED is going to be a long process (cost-wise) but I'm going to order a couple of these to test with the PAR meter just in case by some freak chance they're awesome: http://www.homedepot.com/p/Commercia...3161/205331022
OK, these are kind of cool but I need to do some more testing. The box says 3200 lumens and 35 watts; but PAR is what we're really after. Crude test results:

At 18" away from the fixture (center) they show a PAR of 40 versus a 3-bulb T8 shop light with full-spectrum bulbs at 50 PAR... but that's one 36-watt LED fixture versus three 32-watt T-8 bulbs (96 watts); so it's mildly impressive.

At 18" from the center of a four-bulb T5HO fixture I get 150 par but that's four 54-watt tubes (216 watts). The four-bulb standard T5 shows 65 PAR from four 28-watt bulbs (112 watts).

I'll put the kill-a-watt meter on all of them when I get a chance, so we can look at total watts including any ballast or other circuitry. Also, the T8, T5 and T5HO could/should probably have all new bulbs for the test... although the bulbs are only going to be "new" when you put them into service, I don't know if they all have the same hours running or not.

The LED fixture has a very opaque plastic "diffuser" that I would like to try to remove, just to see how much it impacts the PAR reading.

The LED fixture is also very narrow, so it's not going to cover as much area as the four-bulb fixtures; but the cost is about 1/2 to 1/4 what I paid for the T5 and T5HO fixtures respectively... and the power use is 1/3 to 1/6; plus the bulb life should be 10x that of either of the T5's.

The LED fixtures have a neat little plastic "link" so that you can hook the fixtures tight end-to-end or also a short (about 12") link-cord in case you want to raise or lower the fixture independently... either way you can have up to 9 fixtures with one power cord & plug.

Now, linking the two LED fixtures with the supplied cord and laying the fixtures side-by-side gives me a 16" wide x 48" long pair that reads 60 PAR at the center from 72 watts. And lightweight, at 3-pounds per fixture it wouldn't take much to support them.