HPS vs. LED: The costs of horti lighting

In our latest blog post we detailed why, despite their proven advantages, some growers are still hesitant to transition to LEDs from HPS lights. If you weren’t convinced of the advantages of LEDs then, in this article, we talk numbers, detailing the advantages of HPS vs. LED on your wallet. 

As we highlighted LEDs boast a range of benefits compared to their HPS counterparts. Yet with lighting being one of the most energy-intensive activities of an indoor or glasshouse farming operation, it is more often than not their cost and efficiency that is the deal breaker.  

The Economics of HPS vs. LED

Choosing horticultural lighting is one of the most important decisions a grower makes before setting up a greenhouse. It is often a large part of both CapEx, Capital Expenses, and OpEx, Operational Expenses.  

Good lighting means good production and given that the fundamental aim of any farm is to create a profitable business, it is tempting to think of the lighting decision as a one-time buy and think completely in terms of CapEx and ROI, Return on Investment. Buy the cheapest, best-looking lighting product and then forget all about it. 

Unfortunately, with rising energy costs, issues with efficiency, and the temperamental nature of new or transitionary farms it is essential you factor in CapEx against OpEx. 

CapEx is a predictable one-time expense and gives you an advantage in the short term. In the long run, however, OpEx changes from month to month so it is more often than not the one to keep a close eye on. 

The Problems with HPS 

As we detailed in our previous article, the two most popular lighting solutions are LEDs and HPS.  

HPS lights tend to be cheaper than LED alternatives, so they offer a low CapEx while offering a single wide spectrum that has been used for many crops in the past. 

The problem with HPS is their efficiency. They may be equally efficient in terms of photosynthetic and energy efficiency at the point of purchase but use them for a few months or years and you will quickly notice a significant drop in both aspects. They have an average lifetime of 20,000 hours, so after that, the intensity of their bulbs diminishes to 90% of their potential. Over time HPS lights become less energy efficient, costing you more, and less effective in sustaining the yields and growth they were initially bought for, damaging your ROI. 

This means that whilst they might be tempting in terms of CapEx, in terms of OpEx they are infamous for inducing buyer’s remorse.   

The Advantages of LEDs 

Previously LEDs were significantly more expensive than HPS lights but now with an increase in their production and technological developments, their cost has dropped significantly.  

Saving on Energy and Efficiency  

More significantly, however, is their cost saving in terms of OpEx. In contrast to HPS, LEDs guarantee 50,000 hours of sustained light and in practice have been seen to surpass 100,000 hours. Crucially, LEDs don’t drop considerably in efficiency over this time, so you both save on energy costs whilst maximising the efficiency of your lights.  

Longer Lifespan and Lower Maintenance 

LEDs are not only estimated to last longer in terms of photosynthetic and energy efficiency, but they are also more robust and are easier to waterproof. They are ideal for the wear and tear expected of a busy farming operation and you won’t need to replace your lights for broken bulbs or due to a lack of light output nearly as frequently as you would need to with HPS if at all. More often than not the problems arising with LEDs are due to the driver which can be easily replaced. Meaning no costs as a result of downtime or extra labour.  

Adaptable Light Spectrums mean Higher Yields 

They provide more flexibility than HPS lights, dimmable drivers, and customisable spectra. LEDs allow you to tailor your lights to your specific project to help reduce seed-to-harvest times for increased yearly production cycles and gain increased uniformity across your crop. Maximising your ROI. 

Less Heat

Furthermore, as they have a lower heat output you can also make savings by optimising your HVAC system.  

Better Environmental Impact 

With no toxic elements, LEDs avoid the cost and time required for the compliant disposal of HPS. 

Case Study: Aberystwyth National Plant Phenomics Centre 

The National Plant Phenomics Centre in Aberystwyth, Wales is an internationally renowned research facility. Their research often requires the ability to control and monitor the temperature and lighting conditions within their glasshouses throughout the year. 

In 2021 they decided they would replace their existing 600W HPS lights with 300W LEDs. They chose Kroptek for their established record in improving growth conditions whilst providing environmental and cost benefits from lower energy consumption.  

After Kroptek replaced the HPS fixtures with our 1-to-1 replacement HiKrop Series the gain in energy efficiency reached 50% without taking into consideration the cost of the 100 HPS fixtures that needed annual bulb replacements and maintenance.

The transition to LED lights also reduced the need for active cooling due to the heat from the HPS fixtures.  

“By installing these LED lights, we are making a contribution to help Aberystwyth University’s effort to limit global warming. 96 of the original lights in the robotic greenhouse have now been replaced with Led lights that provide the correct wavelength for plant growth, particularly during winter months. As well as significantly reducing carbon dioxide emissions the new lights will also cut the Centre’s annual electricity bill by around £17,000 [as of 2021 energy prices].”  

Choosing the right lighting solution  

When it comes to HPS vs. LED, therefore, LEDs make up for their higher CapEx with numerous OpEx advantages and further peripheral features which can enhance plant growth and optimize your grow space. 

LED lighting solutions are effective for year-round growth in greenhouses and indoor farms but depending on your budget and grow setup the choice may still not be obvious.  

That’s where our team of horticultural experts come in. If you are still concerned about your lighting solution, contact us today and we can talk you through what the ideal lighting solutions would be for you…

Source: Edward Hewes | Kroptek

Photo: Unsplash

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