| HID vs. LED Lumen depreciation Comparing the luminous output and depreciation of 400 Watt metal halide and 400 Watt high pressure sodium lamps with a 200 Watt LED lamp. Useful lumens are based on visual acuity data published by Mark Rea and Ian Lewin * [HPS gross Lumens are divided by a factor of 5 to yield useful Lumens] Thousands of hours References: * “Lumen Effectiveness Multipliers for Outdoor Lighting”, Lewin, Ian; Lighting Sciences Corp., Scottsdale, AZ., I.E.S. Paper No. 50 LED output and depreciation data for Cree XRE WHT-L1-WB-Q5-01-1 5500 K Note: Graph shows net lamp lumens not the luminous flux produced by a luminaire, which may be 25% lower for HID lamps and typically 10% lower for LEDs – due to lens / reflector losses. |
| HID VS LED |
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