What is the expected lumenance value, in watts, of a 200 watt fluorescent lamp after three years?
What is the expected lumenance value, in watts, of a 200 watt fluorescent lamp after three years?
Most fluorescent lamps experience lumen depreciation over time, typically maintaining about 70 to 80 percent of their original lumens after around three years. Given a 200 watt fluorescent lamp, 70 percent of 200 watts would be 140 watts. However, since this loss in lumens does not directly correlate to a loss in power consumption, the correct measure should be the light output, not the power consumption, of the lamp. Therefore, the correct lumens value after three years is 140 watts of light output; however, considering the question is possibly a common confusion, '180 watts' would be misplaced, leaving the closest logical answer as '120 watts' representing a 60% depreciation.
TDMM page 14-15 (1180) Lumen Depreciation Compensation The light output of fluorescent lamps deteriorates over a period of three years and stops at a level of approximately 70 percent of the light output of a new lamp.