LED light fixtures have multiple advantages over HPS such as yield, efficiency, safety and cost of maintenance. All comparisons are made using Photon setup in the 7-way configuration, against the current market leading 600w HPS. Comparisons will be broken down into energy efficiency, spectral output quality & yield.

Spectrum & Light Quality

When looking at the absorption spectra of light it is clear to see distinct peaks at different wavelengths within the PAR range that are responsible for photosynthesis, this coupled with the McCree curve gives us an arsenal of material that allows us to make informed decision when choosing a light.

Photon LED™  FullPhotoSpec™ Vs Market Leading 600W HPS

Photon LED FullPhotoSpec vs McCree Curve Chart

Figure A.

Leading HPS Spectrum vs Mcree Curve Chart

Figure B.

Comparing the two spectrum's (fig. A & fig. B), you can see Photon LED™ has broader, more well-rounded wavelength distribution covering a larger majority of the PAR range than the Market leading HPS. The HPS light spectrum sits largely between 550 and 670nm, this is due to the Sodium (the main element used) which is found within the bulb. Because of this the spectrum cannot be altered and for the most part HPS lamps will always produce this “golden” hue, and while they’re a tried and tested grow light we firmly believe that a full spectrum light source will outperform HPS; promoting healthier plants and a greater rate of growth. Comparing both HPS and Photon LED™ spectrums to the McCree Curve, you can clearly see how Photon LED™ closely mimics the spectral distribution pattern whereas HPS does not.

Its also worth noting that traditional HPS setups and reflectors have inefficient light spread/coverage when compared against Photon. The single source, 360° emission HPS bulb emits multi directional light which has to be focused downwards losing PAR photons through light degradation. Photon diodes emit light at 90°, directing all light towards your plants so none is wasted whilst ensuring a homogeneous coverage.

Energy Efficiency

LED light fixtures are renowned for their efficiency and their ability to produce enormous PPF and PPFD readings. Photosynthetic Photon Efficacy (PPE) is a useful measurement for grow light comparisons as PPE measures how effectively a light turns electricity into PAR photons; measured in μmol/J where the higher the measurement, the better the light. Photon measures in at 2.02 μmol/J whereas HPS’ can measure anywhere between 1.3 and 1.91 μmol/J (1.91 being the market leader). Following on from PPE, the maximum PPFD for Photon measures in at 1467 μmol/m2/s compared   to  HPS’   810.   As    previously     said    single    PPFD  measurements

tend to only show the maximum figure obtained whereas a more practical measurement is an average PPFD reading taken over 1m2. By showing the number of PAR photons as well as its spread across 1m2, the quality of light produced and light distribution can be easily ascertained and compared. Photon averages 732.2 μmol/m2/s whereas most lighting companies (such as the market leading HPS manufacturer) withhold this information opting to only share the maximum PPFD; A single reading taken directly under the middle of the light would appear more impressive to consumers. Photon LED™ will always publish PPFD readings and charts for our lighting systems allowing you to make informed decisions when obtaining your new light.


Another bonus of LED technology is that fewer watts are drawn to achieve a high PPE. Photon LED™ 7-way draws only 455w to produce more PPF than a 600w HPS, saving 145 Watts. Photon units are also passively cooled through their solid state heatsink technology, this coupled with an overall cooler running temperature not only allows more light fixtures in a certain space but also reduces the risk of fire. The heat expelled from Photon LED™ is significantly less than HPS bulbs, this also has the potential to further reduce bills as air cooling units would have to draw less electricity to cool a given grow space, and on smaller operations, air conditioning may not have to be used at all. Overall, we estimate a 30% reduction in electricity costs when compared to HPS.