Before you said 2x 100 watt lights do not equal a 200 watt light.
And they don't.
The typical 100 watt incandescent light bulb produces around 1100 lumens. The same exact bulb in a 200 watt construction produces around 2800 lumens.
What you and others like you simply
REFUSE to understand is that the wattage, in the grand scheme of things, is irrelevant. That's the entire point behind what I and others have said: That putting two of the same exact wattage together doesn't mean shit. It's based on the actual amount of light the fixture produces, not whatever wattage it happens to be at the time.
If you want to go to extremes, the other example is HPS.
My 600 watt High output HPS bulb pounds out 90,000 lumens. I could get a 1000 watt fixture with the same brand bulb that puts out 150,000 lumens.
Now, this is where it gets dicey, because even though 90,000 x 2 = 180,000, which is in the grand scheme of things brighter than the 150,000 lumens of the 1000 watter, you're still not going to get 150,000 lumens of intensity over the same area
UNLESS you stack the bulbs side by side, which completely defeats the purpose.
If you spread the two 600's out to cover a larger area, you're actually right back to where you started from with 90,000 lumens covering a larger area. It doesn't mean you have 150,000 lumens over any given plant like you do with the 1000 watt fixture. The only way you would actually do that is to mount both 600 watt bulbs in the same fixture or
VERY close together in a small area. That would give you the 180,000 lumens.
BUT...and there's
ALWAYS a but...
You would be running 1200 watts of power to pull that off. What's the point? You're better off just buying the 1000 watt HPS and calling it a day.
It's not just the lumens that matter either, it's the area you're covering. It's the application. It's common sense.
Obviously, you don't have any...which explains why you can't grasp any of this.
So to review the OP's case: he has a 3.5 x 8 foot scrog area he's going to grow in. The typical 1000 watt HPS will cover a 6 x 6 effectively. The typical 600 watt HPS like I've got will do a 4 x 4 nicely. So which would he be better off with?
Well, in his case, the two 600's would be the way to go. Reason being, although the 1000 is going to be much brighter, it's going to fall short of covering the entire length of the grow. Now, although 1000 watts is nice to have, and would be the way to go if money were no object, the 600's are a bit cheaper and do a fantastic job. (
MUCH better than the shit lights he's using.)
That would give him good, strong, 90,000 lumens 4 feet wide and 8 feet long,
PERFECT for his grow. But it's going to triple his power bill over the cheap shit he's using now.
Now, he
COULD get some good 400 watt cob light fixtures (2 nice linear setups would work perfectly) and that would save about 25% on the power bill over the HPS fixtures,
BUT (there's that but again) the light fixtures cost three times as much.
Either way, you're
NOT going to get superior lighting for cheap. You're either going to pay big bucks up front (cob) or big bucks over the long haul via the power bill later (HPS).
With the shit he's using, he'll never in his life get good yields. Ever.