Suppose you are the physical plant manager for a new hotel with many light fixtures. You need to decide if you should use 15 watt compact fluorescents or 60 watt incandescent, each giving equivalent amount of lumens of light. The compact fluorescents cost $4.49 and last 8 years, while the incandescent light bulbs cost $0.60 and last 1 year (thus have to be bought 8 times). However the compact fluorescents save $4.96 per year in electricity costs. (This assumes that electricity costs 11 cents/kWh, lighting is used 2.75 hours per day x 365 days x 45watt savings.) Which light bulb should you use? Make the calculation using two different discount rates: 2% or 5%. You can use the Excel chart below to start your work. Print your results. Cash Outlay for Investing in Lighting