Metal Halide Fixtures: Components, Applications, and LED Conversion Guide

A metal halide fixture is a commercial or industrial lighting system with five essential components:

• Fixture type – Including high bays, shoeboxes, flood lights, wall packs, and canopy lights
• HID bulb – The metal halide lamp that screws into the fixture socket
• Ballast – Regulates voltage and current to operate the HID bulb from standard AC power
• Reflector – Focuses and directs the omnidirectional light output
• Mounting system – Hardware for secure fixture installation

Understanding Metal Halide Technology

Metal halide belongs to the High Intensity Discharge (HID) lamp family, along with mercury vapor, high-pressure sodium, and xenon bulbs. All HID lamps require ballasts to regulate electrical power for proper operation.

Metal halide bulbs produce omnidirectional light, similar to traditional incandescent bulbs. Light radiates in all directions from the arc tube.

To control this broad light distribution, fixtures use highly reflective mirror-finished reflectors that gather and redirect the light output. This focusing system allows precise light placement for specific applications.

Performance Characteristics

Metal halide lamps exhibit several operational traits that affect their suitability for different applications:

• Initial brightness – Very high light output when new
• Warm-up time – Requires several minutes to reach full brightness
• Restrike delay – Must cool down before restarting after a power interruption
• Lumen depreciation – Light output decreases significantly over time

Metal halide produces much whiter light compared to high pressure sodium, which creates distinctive orange illumination.

Applications for Metal Halide Fixtures

Metal halide fixtures serve high-lumen applications across industrial and commercial facilities:

Indoor Applications

• Gymnasiums and recreational facilities – LED gymnasium lights
• Warehouses and distribution centers – LED warehouse lights
• High bay and low bay industrial lighting – LED high bay lights and LED low bay lights
• Manufacturing and shop lighting – LED shop lights
• Factory production areas

Outdoor Applications

• Parking lot lighting – LED parking lot lights
• Stadium and sports field illumination – LED stadium lights
• Street and roadway lighting – LED street lights
• Area and perimeter lighting – LED area lights

Common Wattage Categories

• High-wattage applications (1000W-2000W) – Large stadium and industrial fixtures
• Medium-wattage applications (250W-400W) – Parking lots and warehouse high bays
• Lower-wattage applications (100W-150W) – Wall-mounted fixtures and smaller area lighting

Converting Metal Halide Fixtures to LED

LED technology has evolved to provide viable alternatives to metal halide systems. Early LED products lacked sufficient light output and cost effectiveness. Today’s LED fixtures offer compelling advantages for facility managers and contractors.

LED Advantages Over Metal Halide

• Energy efficiency – LED fixtures typically use 50 to 75% less energy than equivalent metal halide systems
• Extended lifespan – Quality LED fixtures maintain 70% of initial light output for 100,000+ hours compared to 12,000 to 20,000 hours for metal halide
• Superior light quality – Most LED products provide a high Color Rendering Index (CRI) for better visibility and color accuracy
• Instant operation – No warm-up time or restrike delays
• Reduced maintenance – Fewer replacements and lower labor costs

Metal Halide Lamp Degradation

Understanding metal halide performance decline helps justify LED conversion projects:

Lifespan and Light Output

Metal halide bulbs typically last 12,000 to 20,000 hours, but light output degrades significantly during this period. Many facilities replace lamps at 50-60% of rated life due to insufficient illumination levels.

A typical degradation pattern shows:

• At 50% of rated life, approximately 70-80% of initial lumens remain
• At 75% of rated life, approximately 50-60% of initial lumens remain
• Color shift – Aging lamps often develop a blue or violet tinting

Important: Fixture installation, modification, or electrical work should be performed by qualified electricians in accordance with local electrical codes and safety requirements.