Agenda - 10-19-1993 - VII-B - Laserfiche WebLink

Browse Search

6 BOCC Page 5 October 14, 1993 typical light fixtures contains two forty-eight inch long florescent tubes and consumes seventy-five watts per hour to produce 5300 lumens. Assuming each of these light fixtures operates approximately eleven hours per day for five days a week and fifty weeks a year, each fixture consumes 206 kilowatt hours per year at a cost of $15.50 per year (assuming cost of electricity at $0.075 per kilowatt hour) . The newest energy efficient florescent lighting technology of similar configuration is designated as T-8 lighting and uses two forty-eight inch long 32-watt tubes with electronic ballasts and consumes 58 watts per hour to produce 5800 lumens. One T-8 fixture has a yearly power consumption of 160 kilowatts and an operating cost of $11.96 at $0.075 per kilowatt hour. To determine the value and cost of a typical re-lamping project it is necessary to evaluate a sample re-lamping project in comparison to maintaining the status quo over a five year period. There are a number of factors that must be clarified in order to provide a comprehensible evaluation: 1) the County' s labor cost of replacing the tubes and ballast in a single fixture is approximately $20.00 including time to actually replace the material, get the material, travel, set-up, etc. ; 2) labor costs per fixture can be reduced by as much as fifty to seventy-five percent by replacing a number of fixtures simultaneously (eliminating travel time, etc. ; 3) when estimating the value of a significant number of ballasts and tubes that will be replaced but have not yet failed, one can reasonable assume that the average fixture has approximately one-half of its useful life remaining; 4) the rate life of both T-12 lamps and T-8 lamps is 20,000 hours or about seven years at the number of hours per year operated in County buildings - actual life is approximately three years; 5) the life span of an "energy saving" ballast is approximately five years while the life span of an electronic ballast is approximately ten years; 6) at the end of a five year period, every "energy saving" ballast in a sample group will have been replaced once, yet still have not more remaining life at the end of the period than an electronic ballast; 7 ) the labor cost of replacing a ballast and lamps is essentially the same as replacing ballast alone.