Food producers growing in indoor farming environments like greenhouses or polytunnels will no doubt be well aware of the importance of horticultural lights. But which technology is best – High Pressure Sodium (HPS), LED, or perhaps a mix of both?

Choosing your tech: which system is right for you?

HPS lights enjoy market share because they are long-established products that are standardised among manufacturers, and offer compelling benefits to some growers. However, they face growing competition as LED technology continues to improve.

Key to the popularity of HPS lights is their massive raw light output, which is especially good for flowering[i]. Yields are high, particularly with larger plant varieties. Traditionally, HPS lighting installations have also had lower start-up costs than their LED counterparts.

However, HPS products consume considerably more power to generate light than comparable LED grow lights, with significant implications for carbon footprint and operating costs. This is exacerbated as they also produce substantial heat, which often needs ventilation equipment – and therefore more energy – to remove. Additionally, HPS grow bulbs diminish in intensity significantly over time and must be replaced every 12-18 months, resulting in extra operating costs.

The HPS price advantage is being steadily eroded as LED prices drop – and LEDs offer many further advantages besides.  LED grow lights combine controllability, precise spectral outputs, advanced optics, and thermal management engineering to convert nearly 100 per cent of consumed power into growth-targeted light energy. Accordingly, LED grow lights can produce high yields while consuming far less energy than their HPS counterparts.

Ironically, LEDs’ electrical efficiency can sometimes be a disadvantage in that most greenhouses using only LED technology will need some heating, especially in winter. Accordingly, growers may use a mixed solution, where they retain HPS lighting to maintain warm greenhouse conditions, with supplementary LEDs to boost light levels and optimise spectral tuning.

The flexibility of the Intelligent Grid

Whichever approach you choose – LED, HPS, or a mixture – the most important element is having the flexibility to optimise your horticultural lights to your particular requirements. One example of how this could be achieved is by installing a system like IGS’ Intelligent Grid, which gives users a modular design comprised of a transformer, hubs, connectors, and busbars that can be readily configured to support HPS lights together with supplementary multi-spectrum and variable wavelength LED lighting.

If you later want to change the mix of LED and HPS lighting, or even replace some of the HPS lights with heat pipe systems, you should be able to do so easily. The installation and reconfiguration can furthermore typically be done without the need to employ external contractors. The modular design means that you can continually adapt your greenhouse climate to accommodate changing seasonal and growing cycle demands, while also modifying your heating strategy as accumulating experience dictates.

Additionally, the Intelligent Grid’s IoT-enabled technology gives you access to solutions including sensors, cameras, and other devices which can all be connected to the Cloud for precision control, monitoring and data analysis. The information generated can then inform decisions related to maximising crop yield, quality, and consistency, while minimising your operation’s energy consumption and carbon footprint.

To learn more about how the Intelligent Grid can become your cost-effective greenhouse lighting and environmental control system, please contact our the team.


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