KR-G100T vs KR-G100T-F: Two 110 W UFO Canopy Lamps, a Copper Heat Pipe and a Glass Lens, and Why PPF Moves from 250 to 258 umol/s

Two outdoor-looking arguments dominate grow-light marketing: wattage and PPFD. Inside a single manufacturer’s catalogue, the more useful comparison is narrower — what changes between two SKUs that share one 110 W platform, one optical format and one housing, and what that change costs you in light delivered.

Buying a lamp at a fixed wattage feels like a solved problem: pick the wattage, pick the beam, done. Manufacturer catalogues show it is not, because the same 110 W platform is often sold in more than one internal configuration, and the configurations do not produce identical photon output. The KR-G100T and the KR-G100T-F are exactly that case: identical power rating, identical recipe code, identical dimensions and weight, identical beam angle, and measurably different PPF, PPFD and luminous flux. This article explains where the difference comes from, how to read a three-distance PPFD curve, and which of the two internal configurations suits which installation. It does not cover HPS replacement arguments or dimming interfaces, neither of which the manufacturer publishes for this family.

What Actually Changes Between Two 110 W Lamps

The shared platform is the starting point, because a difference only means something against a baseline.

Against that common base, two parameters move:

• Power supply. The KR-G100T is specified with a Meanwell HBG driver; the product page also notes that a lower-cost square power supply is available. The KR-G100T-F is specified with a square XLG-150-H-AB supply.
• Light output. PPF 250 → 258 µmol/s, PPFD @0.3 m 1331 → 1350 µmol/m²/s, luminous flux 16,794 → 17,348 lm.

Everything else — recipe code, emitter mix, geometry, mass, beam angle and thermal rating — is held constant, which is what makes the output delta attributable to the internal configuration rather than to a different lamp wearing a similar name.

PPF, PPFD and Flux Are Three Different Measurements

PPF is the total photosynthetic photon flux a fixture emits, expressed in micromoles per second (µmol/s). PPFD is the photosynthetic photon flux density arriving at a surface, expressed in micromoles per square meter per second (µmol/m²/s), and it is the quantity a canopy actually receives. Luminous flux is a photometric quantity in lumens, weighted by human vision, and it is not a plant metric.

Keeping them apart prevents a common misreading. PPF is a property of the luminaire and does not depend on where you stand; PPFD depends on distance, because the same photon stream spreads over a larger area as it travels. Luminous flux is useful for comparing against luminaires specified the human-facing way, and nothing more.

Applied to the two SKUs:

• PPF: 250 µmol/s (KR-G100T) versus 258 µmol/s (KR-G100T-F). That is a +3.2 % difference, derived here by reading the two official figures.
• PPFD @0.3 m: 1331 versus 1350 µmol/m²/s, a +1.4 % difference (derived).
• Luminous flux: 16,794 versus 17,348 lm, a +3.3 % difference (derived).

The official documentation does not publish an efficacy figure in micromoles per joule. If a reader needs one, the arithmetic is available: 250 µmol/s ÷ 110 W ≈ 2.27 µmol/s per watt and 258 µmol/s ÷ 110 W ≈ 2.35 µmol/s per watt. These two numbers are conversions performed for this article, not manufacturer ratings, and they should be labelled as such wherever they are quoted. The stated tolerance on these photometric and electrical values is ±10 %, which is wider than the delta between the two SKUs — an important sanity check, and one returned to below.

Power Supply Choices: Meanwell HBG versus XLG-150-H-AB

A constant-current LED driver is the device that converts mains AC into the regulated current the emitter string requires, and its topology sets both the achievable drive level and the conversion losses that appear as heat inside the housing.

Both configurations are specified at the same 110 W and the same AC110 V input, but they are not the same driver family. The Meanwell HBG unit is the long-established pairing on the KR-G100T and is designed as a potted, water-resistant class of driver; the product page’s note about a lower-cost square supply points to where the trade-off sits. The KR-G100T-F is specified with a square XLG-150-H-AB supply, a 150 W-class driver running below its ceiling in a 110 W fixture — which is the usual reason a manufacturer can push a little more current into the same emitter string and report a slightly higher PPF.

Two practical consequences follow. A driver running below its rated maximum generally runs cooler, and case temperature rise is specified identically for both SKUs at Tc 30 K. And because the SKU difference lives in the driver rather than in the optics, the two lamps are physically interchangeable in an installation: the same Ø21 cm × H25 cm envelope, the same 2.5 kg mass, the same hanging hardware.

Thermal Path: Copper Heat Pipe in Zero-Distance Contact with the Light Source

A heat pipe is a sealed tube in which a working fluid evaporates at the hot end and condenses at the cold end, moving heat by phase change rather than by conduction alone. Its advantage over a solid metal slug is a much higher effective thermal conductivity across the length of the path.

The official description for this family specifies a glass lens and, in the manufacturer’s own wording, a copper heat pipe directly with the zero-distance heat bonded, cited as the basis for higher reliability. Zero-distance bonding means the heat pipe is coupled to the source without an intervening air gap; air is a poor conductor, and an interface gap is where junction temperature and rated life are usually lost. The specified figures that depend on that path are Tc 30 K case rise and a 50,000-hour rated life with the note Ta < 25 °C — a conditional figure, which is the honest way to publish lamp life.

Official KR-G100T product image (media 4441). The manufacturer specifies a glass lens and a copper heat pipe bonded in zero-distance contact with the light source.

Reading the Three-Distance PPFD Curve

The published irradiance values are given at three distances, and the manufacturer’s recommended throw is 0.2–2 m, for indoor and windowless-basement installations. That pairing is the whole story of how to read the lamp.

The inverse-square behaviour is visible immediately: tripling the distance from 0.3 m to 1 m reduces PPFD by roughly a factor of eleven at these points, so hanging height is the single largest lever an installer controls. The 2 m end of the recommended range is therefore a coverage statement rather than a performance statement — useful for low-intensity, wide-area work, and not a position at which to expect canopy-level intensity from 110 W.

Turning PPFD into a dose is the other half of the job. Photoperiod and intensity combine into the daily light integral, and Michigan State University Extension’s supplemental lighting guidelines for young plants and its light-management resource both work through that combination and where photoperiod stops being able to substitute for intensity [1][2]. At 0.3 m, where a canopy under this lamp would sit in a dense single-tier layout, the published values sit in the high-intensity band; at 0.5 m and beyond they belong in a lower-intensity, longer-photoperiod regime. Growers targeting secondary metabolite profiles rather than biomass gain from the same arithmetic, since light quality and quantity are both regulators of that pathway in the peer-reviewed literature [3].

The ±10 % tolerance on the published values deserves a final note. It is larger than the 1.4–3.3 % gap between the two SKUs, which means the honest reading of the comparison is directional: the -F configuration is built to deliver slightly more photons from the same power, and a single point measurement on a lux meter or PAR meter is not the way to detect the difference. Comparing the two SKUs against a common benchmark, and averaging several measurement points, is.

Side-by-Side Specification Comparison

Official KR-G100T and KR-G100T-F specification table (media 5126), the source of every figure in the table above. The product page separately states PPFD greater than 1200 µmol/m²/s at 0.3 m, consistent with the 1331 µmol/m²/s datasheet value.

Which Configuration to Choose — Application Guidance

The decision reduces to one question: does the installation need the last few percent of photons, or the lowest acquisition cost per unit?

Suits KR-G100T: rooms where the driver is a known, serviceable item and matching the existing fleet matters more than a marginal output gain — for example a multi-lamp room being extended with the same model already on the ceiling. The Meanwell HBG pairing, with the lower-cost square supply option noted on the product page, also gives the widest cost flexibility when a project is priced per unit.

Suits KR-G100T-F: installations where the lamp count is fixed by rack geometry or ceiling structure and the only remaining lever on total delivered photons is per-lamp output — single-tier benches at a fixed 0.3–0.5 m canopy distance are the typical case. The XLG-150-H-AB supply running under its ceiling in a 110 W fixture is the reason the -F configuration is the higher-output of the two.

Neither is the right choice when the requirement is dimming or scheduling, because no dimming interface is published for this family. That is a separate product decision in the control layer. Both SKUs are specified for indoor and windowless-basement use across a 0.2–2 m throw range at −30 to 40 °C, with CE / RoHS / FCC listings.

Koray Opto-Electronic has built this family on 17 years of experience and 300+ domestic and international patents across its horticultural lighting and control product lines [4].

FAQ

What is the actual difference between the KR-G100T and the KR-G100T-F?

Both are 110 W / AC110 V lamps on the same S15 recipe, housing, emitter mix, 100° beam and thermal platform. The KR-G100T is specified with a Meanwell HBG power supply and 250 µmol/s PPF; the KR-G100T-F uses a square XLG-150-H-AB supply and is specified at 258 µmol/s PPF, with correspondingly higher PPFD and luminous flux.

Why is the PPFD figure different at 0.3 m, 0.5 m and 1 m?

Because PPFD is a density that falls as the beam spreads. The same lamp is specified at 1331, 457 and 114 µmol/m²/s at those three distances for the KR-G100T, and 1350, 462 and 115 µmol/m²/s for the KR-G100T-F.

Does the datasheet give an efficacy figure in µmol/J?

No. The manufacturer publishes PPF in µmol/s and power in watts but no µmol/J rating. Dividing the two gives approximately 2.27 for the KR-G100T and 2.35 for the KR-G100T-F; those values are reader conversions and are not official ratings.

Can the difference between the two SKUs be measured in a grow room?

Not reliably from a single reading. The published photometric tolerance is ±10 %, which is much larger than the few-percent gap between the SKUs, so a comparison needs a common benchmark and several averaged measurement points.

Can the spectrum be changed?

Yes. The product page states that the spectrum is customisable, including UV and far-red options, for both configurations.

References

1. Michigan State University Extension — Supplemental lighting guidelines for young plants: https://www.canr.msu.edu/resources/supplemental_lighting_guidelines_for_young_plants
2. Michigan State University Extension — Light Management in Controlled Environments: https://www.canr.msu.edu/floriculture/resources/light-management
3. PubMed Central — review of light regulation of secondary metabolite synthesis and accumulation: https://pmc.ncbi.nlm.nih.gov/articles/PMC12358498/
4. Official KR-G100T product page (product ID 6869): https://koraylights.com/product/110w-ufo-led-plant-grow-lamp-kr-g100t/
5. Official KR-G100T product PDF (media 5125): https://koraylights.com/wp-content/uploads/2020/02/KR-G100T.pdf
6. USDA Agricultural Research Service (institutional reference for controlled-environment research): https://www.ars.usda.gov/
7. Lighting Facts programme (US DOE-supported lighting performance labelling reference): https://www.lightingfacts.com/