In 1962, the invention of the high pressure sodium bulb represented a breakthrough in energy efficient and high-intensity lighting technology. Soon after its invention, HPS bulbs were installed in street lights nationwide, and their high lumen output provided greater nighttime visibility for drivers on streets and highways. The bulb also became adopted for both indoor and outdoor industrial purposes. Due to these different uses, the HPS bulb has a variety of end-users who have different needs when making lighting decisions. For many years, the HPS bulb dominated the industrial market because of its high lumen output, its impressive life-span, the efficiency with which it converted electricity into light, and the spectrum of its light output. While other bulbs have been developed in recent years that are superior in terms of energy efficiency, the HPS bulb has risen in popularity with indoor growers; these horticulturalists value the red spectrum light that the HPS bulb's chemical reactions produce, as it is ideal for a plant's flowering stage.
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Discover how the bulb works and what it is made of.
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Find out how the bulb has evolved over time and hear from an expert.
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Find our more about the Bulb Brigade, part of Georgetown’s CCT Program.