shrubs_n_bulbs

T5 or Metal Halide?

shrubs_n_bulbs
15 years ago

I'm seeing a lot of articles about the benefits of switching from HID lighting to T5 fluorescents. The typical articles, like this example, describes how T5 lamps are now more lumen efficient, have better CRI, equal or longer life, and better lumen maintenance than HID systems.

Am I missing something, or are these articles comparing a cutting edge 2005 T5 lighting setup with a 20-year-old obsolete HPS system? They describe HID lamps with 60 lumens/watt, CRI of 20 (HPS maybe, but surely not metal halide), ballast losses of 60+W on a 400W bulb, and lumen depreciation of 40%+. Then I see some things like "luminaire efficiency" and "pupil correction" sneaking in. Is there a massive marketing scam to replace obsolete HID lighitng with new T5 lighting, when it would actually be better to replace it with new HID lighting?

Do T5 lamps really compare with a modern metal halide lamp? And does the comparison work for plants?

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