Case Study - Mercer Island Country Club
This project consisted of replacing the Mercer Island County Club’s tennis facility lighting of their seven indoor tennis courts. The existing lighting was comprised of 17.7 1,000-watt metal halide fixtures per court, for a total of 124 for the entire facility. The metal halides were suspended at 16’ aimed at the 38’ ceiling, which produced an indirect light source. The seven courts were located in two separate buildings. Building #1 contained three courts and recently had installed a new reflective ceiling, providing an optimal reflective surface to support the Courtlite indirect lighting system. Building #2 contained 4 courts with a painted drywall ceiling, which provided marginal light quality due to the poor reflective surface. Courtlite designed an energy efficient indirect lighting system that reduced the energy consumption while radically increasing the light quality, which provided manual management for maximum savings.
Courtlite approached this project with several objectives: energy reduction, increased light quality, system manageability, and substantial project funding from Puget Sound Energy (the local utility company). Mercer Island Country Club opted to install the Courtlite Indirect lighting system, consisting of 18 10 lamp T5 fixtures per court. The Courtlite fixtures were suspended from the existing strut 16’ above the floor, and 6’ feet beyond the sidelines. The proprietary design of the fixture allows the light source to be aimed 5 degrees towards the center of the court’s ceiling, providing a directional indirect light source. The existing lighting system was operating at full capacity 20 hours per day, as the 1,000-watt metal halides take too much time to warm up. Due to the instant ON/OFF feature, the Courtlite Indirect fixtures are designed to allow the facility to turn off individual vacant courts, unlike the existing metal halides that could not be switched off because of the long warm-up time. The manual switching will allow the club to reduce their energy consumption by an additional 20%-30% annually. In addition to the new lighting system, Courtlite worked with Insulpro to also provide a new reflective ceiling surface in Building #2. The final results of this project include a reduction of 413,000 Kwh per year(44% with out management) with an annual savings exceeding $29,000. Equally important, there’s been a dramatic increase in light quality.
| Fixture description | Existing indirect | 8′ 10 lamp 11 fix indirect |
| Quantity of fixtures | 122 | 127 |
| Lamps per fixture | 1 | 12 |
| Lamp type | 1000 W M/H | 54-W T-5 HO |
| Watts per fixture | 1080 | 585 |
| Total watts per court | 18,822 | 10,613 |
| Total watts all courts | 131,754 | 74,295 |
| Operating hours per day | 20 | 20 |
| Operating days per week | 7 | 7 |
| Operating weeks per year | 52 | 52 |
| kWh per year | 948,628 | 534,924 |
| Cost per kWh | $0.06094 | $0.06904 |
| kWh cost per year | $57,809 | $32,598 |
| Demand KW per month x 12 | 1572 | 888 |
| Cost per demand KW | $5.55 | $5.55 |
| Total demand cost | $8,724 | $4,928 |
| Total energy cost per year | $66,533 | $37,526 |
| Total savings per year | $29,007 | |
| Savings percentage | 44% |
