Fluorescent light bulbs are in a class of lights called “energy-efficient lighting.” They emit a lot of light for the small amount of energy they require to operate. HPS light bulbs are in a class of lights called “high-intensity discharge.” They use a lot of power to produce intense amounts of light.
Lumens are a unit of measurement used to gauge light intensity. A 400-watt HPS light bulb can produce up to 50,000 lumens, or 125 lumens per watt of power used. A 42-watt fluorescent light bulb can produce around 2,780 lumens or 66 lumens per watt of power used.
Each type of light bulb is rated to last for different amounts of time. HPS light bulbs can last from anywhere between 15,000 and 24,000 hours, depending on the wattage. Fluorescent light bulbs are rated to last for between 6,000 and 10,000 hours, depending on the wattage.
Both HPS and fluorescent light bulbs contain mercury. On average, a fluorescent light bulb contains about 5 mg of mercury. A 250-watt HPS light bulb will contain around 15 mg of mercury.
Turning a fluorescent light bulb on and off too often can shorten the life of the bulb. Both types of bulbs are offered in a variety of shapes and wattages. Each shape and wattage level has a different recommended application.
Fluorescent light bulbs are used both indoors and outdoors. HPS lamps, while they can be used indoors, are typically used outdoors or in warehouse-type settings.