Compared with HPS / HPM / MHL

Induction vs. HPS / HPM / MHL

High Intensity Discharge (HID) lamps — including High Pressure Sodium (HPS), High Pressure Mercury (HPM), and Metal Halide (MHL) — have been the traditional choice for outdoor and industrial lighting. Induction lamps offer a compelling alternative with significant advantages.

Technology Comparison

Feature	Induction	HPS	MHL	HPM
Average Lifespan	60,000-100,000h	24,000h	15,000-20,000h	16,000-24,000h
Lumens/Watt	65-80	90-130	65-100	40-60
Color Rendering (Ra)	80+	20-30	65-90	40-50
Color Temperature	2700-6500K	2000-2200K	3000-5000K	3500-4000K
Warm-up Time	< 30s	3-5 min	3-5 min	5-7 min
Restrike Time	< 5 min	5-10 min	10-15 min	5-10 min
On/Off Cycling	No impact	Reduces life	Reduces life	Reduces life
Lumen Depreciation	Slow (~70% @ 60k)	Moderate	Fast (~50% @ 10k)	Fast
Contains Mercury	Yes (small amount)	Yes	Yes	Yes (large amount)

Induction Advantages Over HID

• 3-5x longer lifespan — dramatically fewer lamp changes
• Instant restrike — no waiting after power interruption
• Excellent color rendering — Ra 80+ vs. 20-30 for HPS
• Better color quality — neutral white vs. yellow/orange HPS
• No cycling penalty — frequent on/off doesn't reduce life
• Slower lumen depreciation — maintains brightness longer
• Lower maintenance — fewer replacements, less labor
• Better visibility at night — higher S/P ratio

HID Advantages

• Lower initial cost — fixtures and lamps are cheaper
• Higher peak efficacy — HPS can reach 130 lm/W
• Wider acceptance — familiar to contractors
• Very high wattage options — up to 1000W+

Real-World Performance

While HPS has higher raw lumens per watt, the actual visibility advantage is much smaller due to:

1. Poor color rendering — HPS's yellow light distorts colors and reduces object recognition
2. Low S/P ratio — HPS provides poor scotopic visibility at night
3. Fast lumen depreciation — HPS loses 30-40% output long before end of life
4. Ballast losses — HID magnetic ballasts have 10-15% losses