Norman Lamps, Inc.

High Pressure Sodium (HPS) bulbs have been the dominant technology for outdoor area lighting, street lighting, and industrial applications for decades. Their distinctive golden-orange glow is instantly recognizable on roadways, parking lots, and warehouses worldwide. While LED technology is gradually replacing HPS in new installations, millions of HPS fixtures remain in service, and replacement bulbs continue to be essential for maintaining these existing systems.

The primary advantage of HPS lighting is efficiency – these bulbs produce more lumens per watt than most other HID technologies, which translated to lower operating costs when they were installed. A typical 400W HPS bulb produces around 50,000 initial lumens, providing powerful illumination that can cover large areas from relatively few fixtures. They also maintain reasonable light output throughout their rated life (20,000-24,000 hours for standard bulbs), degrading more gradually than metal halide lamps.

The color rendering is the well-known limitation. HPS produces light heavily weighted toward the yellow-orange spectrum, giving everything that characteristic golden cast. The CRI is quite low (around 20-25), meaning colors are not rendered accurately – blues and greens appear muted or grayish. For applications where color accuracy matters (retail, security cameras trying to identify vehicle colors, architectural lighting), this is a significant drawback. For pure visibility and navigation (roadways, parking lots, warehouse aisles), the color rendering is adequate.

Bulb types include standard HPS for general area lighting, and improved color rendering versions (often called "white" HPS) that sacrifice some efficiency for better color quality. Wattages range from 35W for small fixtures up to 1000W for sports lighting and large area applications, with 100W, 150W, 250W, and 400W being the most common for commercial use. Most HPS bulbs use a mogul (E39) screw base, though some smaller wattages use medium (E26) bases.

Operating characteristics include a warm-up period of several minutes to reach full brightness, and a brief cool-down period required before a hot bulb will restrike if power is interrupted. The bulbs require specific HPS ballasts – they're not interchangeable with metal halide ballasts. As the bulb ages, it may cycle on and off or fail to ignite, indicating it's time for replacement even before complete failure.

Common Applications: Street lighting, parking lots and garages, security and perimeter lighting, warehouses and industrial facilities, outdoor area lighting, roadway lighting, some horticultural applications

Available Wattages: 35W, 50W, 70W, 100W, 150W, 175W, 250W, 310W, 400W, 600W, 1000W. Most common: 100W, 150W, 250W, 400W for commercial/industrial applications.