Determine the cost-effectiveness of adding a dimming daylighting control system to a thin two-story office building (each floor is 24 ft × 1,000 ft) with a window-to-floor area ratio of 30 percent. The building has clear windows (i.e., visible transmittance = 0.78) and is located in Denver, Colorado. The lighting system has a density of 1.1 W/ft2 and operates 3,000 hours per year.

The cost of installing the daylighting system (sensors, controls, and dimming ballasts) is estimated at $45,000. Assume that the cost of electricity is $0.10 kWh and that the interest rate is 8 percent with an inflation rate of 3 percent.