Ready to Cross Over? LEDs Set to Outpace HPS on Nearly Every Front

The cannabis industry has long struggled to balance the high costs of efficiently growing quality products and mitigating its damaging environmental footprint. One of the critical components in the growing process affecting both is lighting. Fortunately, there is a lighting solution that solves these challenges.

The status quo for grow lighting has traditionally been high-pressure sodium vapor lamps [HPSs]. They work when electrical currents flow through ionized gas, often emitting light with a delay. HPS lights have traditionally been an acceptable choice for growing cannabis, mainly during the flowering stage, as their red spectrum encourages vertical growth.

However, the industry’s lightening-speed adoption of light-emitting diodes lights [LEDs] has become an invaluable must-have for growers, and as such, HPS is being pushed out and replaced by the industry's most all-around efficient lights. LEDs are powered by electric currents passing through a semiconductor - a diode. The result is a thermal management system that evenly disperses light and heat throughout targeted growing areas and periods.

A Dim Prospect for HPS

According to the U.S. Occupational Safety and Health Administration, a single HPS lamp contains enough toxic mercury to seriously poison anyone in the same room or within the general area of a broken bulb.  

HPS lamps require a ballast, and, as these lights age over time, they require increased voltage which eventually overtakes the ballast setting, leading to depreciating efficiency over the long run and eventual lighting failure.

In addition to producing light energy, HPSs also produce excessive heat energy for cannabis plants, which is not suitable for all three steps of the growing process. This overproduction of heat energy necessitates additional ventilation and airflow systems, increasing energy use and adding complementary costs to cultivation inputs. This has led to growers’ quick adaptation of LEDs.

A 2021 survey conducted by Cannabis Business Times found that over 62% or more cannabis cultivators use LED at varying percentages for the propagation, vegetation, and flowering stages of production. This is more than double the percentage since 2016.

Cost & Efficiency

A commercial cannabis grow room can consume 2,000-3,000 kWh of energy per pound of products produced. And with electricity - but more specifically, lighting - coming in as one of the highest input costs of production, ensuring that growers are using the most efficient lighting sources can save a significant amount of money and energy usage. 

The estimated cost of a 1,000-watt HPS grow lamp is around $500-$1,000 per year, while LED lights can reach as high as $2,000 for high-quality 500-watt lamps. While this initial investment can be steep, the LED lights' energy savings can justify the price of switching from HPSs to LEDs by paying off the cost to switch in just two to four years.

Where lifespan is concerned, HPS lamps generally last between 20,000 - 24,000 hours, whereas LED lights last between 50,000 - 100,000 hours. Combining these averages with the mid to long-term cost-savings, U.S. consumers and businesses are projected to save $20 billion per year by switching to LED lightbulbs. And with LED lights using up to 70% of the energy that HPSs do while creating less heat and lasting more than twice as long as HPS lamps, the savings generated from switching to LEDs is significant, especially for growers looking to scale up.

Other Benefits of LED

In addition to creating less heat overall than their older counterparts, LEDs also emit light directionally, with a 180-degree angle, whereas HPS lamps emit light over 360 degrees. This makes LEDs efficient at targeting growth areas while preventing infrared light from being wasted on unnecessary areas. 

LED’s low energy requirements make them a compatible choice for renewable energy systems, such as solar panels. Additionally, LEDs tend to be smaller, reducing manufacturing demands for raw materials and production emissions. And if the rate of LED users continues to grow at its expected rate, the U.S. could see CO2 emissions fall by 100 million metric tons per year.  

Time to Make the Switch

While LEDs outpace HPSs on almost every front, there is still some hesitancy from cannabis growers who have traditionally used HPSs throughout their careers. This reluctance to convert from HPSs to LEDs lies in the cost: the cost of buying new, more expensive lights, installation costs, and complementary costs to configure the lights into existing growing models or vice versa.

While HPSs are phased out and replaced by LEDs, there is still room for HPSs currently in use. For growers looking for a short-term indoor cultivation solution for one or two growing seasons, HPSs can be an affordable and easily accessible option. Also, for growers experimenting with new, heat, or drought-resistant strains, HPSs could help replicate harsh environmental conditions indoors, although this is not ideal for most cannabis strains.

The technological advancements of LEDs have infallibly kept pace with the growth of the cannabis industry and, by doing so, has made itself the gold standard for the present and future of cannabis growth.

Employing LEDs for cannabis cultivation brings growers one step closer to achieving economic sustainability and brings the entire industry one step closer to achieving environmental sustainability.