4 Best T5 Grow Lights Comparison Test and Review of 4' x 8 Bulb T5 HO Fluorescent Fixtures
Hello my fellow growers—Nate here. We just wrapped up a test I’ve been really excited about: a head-to-head comparison of 4-foot, 8-bulb T5 HO fluorescent grow lights. I know T5s might not be the “coolest” compared to modern LED grow lights, but they’re still a workhorse for veg rooms, clones, and early plant development.
And honestly, we get the same questions all the time at GrowersHouse: Which T5 fixture is best? Which 8-lamp T5 gives the most even spread? Which one hits the highest output? So we finally brought multiple fixtures in-house, unboxed them, and tested them under our standard lighting footprint: a 5' x 5'.
Test Setup: Same Bulbs, Same Space, Same Process (Variables Controlled)
To keep things as controlled as possible, we ran the same T5 HO 6500K bulbs in every fixture. We literally took the bulbs out of one unit and moved them into the next unit so the bulbs weren’t a variable. That way, the comparison is really about the fixture design—mainly the ballast and reflector performance—using the same power environment in the same physical space.
T5 HO fixtures tested
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Grow Crew 4-foot 8-bulb T5 fixture (now updated to Prism Lighting Science with 120v/240v/277v all-in-one)
We definitely had suspicions going in—and you’ll see in the results that the Quantum BadBoy stood out with a really impressive spread. But (big note here) part of what you need to watch for in T5 HO fixtures is that some units are effectively pushing the bulbs harder—meaning higher wall wattage—depending on the ballast.
Spectrum Snapshot: What a 6500K T5 HO Bulb Looks Like
Before jumping into PAR footprints, I also wanted to show the spectral output of a T5 high output bulb. The spectrum we looked at was a Grow Crew High Output (HO) 4' T5 54W Bulb – 6500K, and it’s broader than a lot of folks expect. You’ve got reds, yellows, some greens, blues, and deep blues—so it’s not a one-note spectrum by any means. (If you’re tracking spectrum details, this is where “broad” matters more than buzzwords like full spectrum.)
PAR Footprints: What the Spread Really Looks Like in a Grow Room
Here’s a key pattern we saw across basically every PAR footprint: intensity tends to be more uniform “wide” than it is “long.” That’s expected with these fixtures because the reflector design typically throws light left-to-right more efficiently than it throws it down the length of the fixture.
This is a practical layout tip for your grow room: you usually don’t need as much cross-lighting sideways from the fixture as you do longitudinally. Knowing that helps you plan fixture placement and overlap, especially in veg areas where uniformity makes plant management easier.
Results: How Different Were the Fixtures?
When we stacked the fixtures up against each other, the variance wasn’t massive overall. Around the outside perimeter, the difference was roughly ~10%. But toward the center, the gap between the least intense and most intense unit was about ~20%—from the Grow Crew to the Quantum BadBoy. All measurements referenced here were taken at 24 inches above the fixtures.
Outside of the BadBoy, the EnviroGro, SunBlaze, and Grow Crew/Prism units were pretty neck-and-neck. Depending on which area you measured, one might slightly edge another, but they were generally in the same performance neighborhood.
Why the Quantum BadBoy stood out
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It appeared to be driving more wattage to the bulbs via the ballast
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It has a larger reflector
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The internal reflective material looked like higher-quality material, which can matter for spread and usable intensity
Voltage Compatibility Note (Important for Commercial Installs)
One practical note: only the Quantum BadBoy T5 and the Grow Crew/Prism T5 can run on 240V—and only the Grow Crew/Prism fixture can also run on 277V. The other fixtures we tested run only on 120V.
Conclusion: Best T5 Grow Light Fixture for Spread and PAR-per-Watt
We also shared an “efficiency” style comparison (PAR over watts). Take it for what it is, but it’s a helpful way to compare output relative to what you’re paying for at the wall. In our testing, the Quantum BadBoy came out on top again.
So if you’re asking me which unit looked like the best overall performer in this test—especially for spread and PAR-per-watt—the Quantum BadBoy was the standout.
What’s Next: T5 Bulb Testing (Including UV Options)
Next up, we’re going to test T5 bulbs directly—same fixture, swapping different bulb models—to see which T5 lamps actually perform best. We’re especially interested with the introduction of bulbs like the Hortilux PowerVEG Full Spectrum with UV options, so keep an eye out for that.
These fixtures are used primarily for vegetative growth, and knowing which one delivers the most even footprint helps us (and you) plan veg layouts that stay uniform, predictable, and efficient.
If you’ve got feedback or want us to test a specific scenario, drop it in the comments. This is Nate from Growers House—happy growing!