­

Relamping fluorescent fixtures: Although fluorescent lamps are generally energy efficient, there are new, even more efficient lamps that use better electrodes and coatings than do older fluorescent lamps. They produce about the same lumen output with substantially lower wattage. Common 40-watt and 75-watt lamps can be replaced with energy-saving lamps of 34 watts and 60 watts, respectively. Energy-saving lamps for less-common fluorescent fixtures are also available.

If you need to replace the ballasts in your fluorescent fixtures, consider using one of the improved varieties. These fluorescent ballasts, called improved electromagnetic ballasts and electronic ballasts, raise the efficiency of the fixture 12% to 30%.

The new electromagnetic ballasts reduce ballast losses, fixture temperature, and system wattage. Because they operate at cooler temperatures, they last longer than standard electromagnetic ballasts.

Electronic ballasts operate at a very high frequency that eliminates flickering and noise. They are even more efficient than improved electromagnetic ballasts. Some electronic ballasts even allow you to operate the fluorescent lamp on a dimmer switch, which usually is not recommended with most fluorescents.

Improving Lighting Controls: Lighting controls are devices for turning lights on and off or for dimming them. The simplest type is a standard snap switch. Other controls are photocells, timers, occupancy sensors, and dimmers.

  • Snap switches, located in numerous convenient areas, make it easier for people in large, shared spaces to turn off lights in unused areas.

  • Photocells turn lights on and off in response to natural light levels. Photo-cells switch outdoor lights on at dusk and off at dawn, for example. Advanced designs gradually raise and lower fluorescent light levels with changing daylight levels.

  • Mechanical or electronic time clocks automatically turn on and off indoor or outdoor lights for security, safety, and tasks such as janitorial work.

  • Crank timers, which are spring-driven and similar to old oven timers, limit lights to short durations where the need for light is brief.

  • Occupancy sensors activate lights when a person is in the area and then turn off the lights after the person has left. They are popular for areas used infrequently, such as warehouses. They also offer security advantages over continuous lighting: when lights suddenly come on, they startle intruders and alert residents and neighbors to motion in the area.

  • Dimmers reduce the wattage and output of incandescent and fluorescent lamps. Dimmers also increase the service life of incandescent lamps significantly. However, dimming incandescent lamps reduces their lumen output more than their wattage. This makes incandescent lamps less efficient as they are dimmed. Dimming fluorescents requires special dimming ballasts and lamp holders, but does not reduce their efficiency.

Fluorescent Lamp Disposal: All fluorescent lights contain small amounts of mercury, and some compact fluorescent lamps with magnetic ballasts contain small amounts of short-lived radioactive material. Because of these hazardous materials, you should not toss burned-out lamps into the trash. Find out if there is a recycling program for them in your community-they are becoming more common-or dispose of them with other household hazardous wastes such as batteries, solvents, and paints at your community's designated drop-off point or during a designated day when you can put such materials with your curbside trash pickup.

Daylighting: Daylighting means using daylight for indoor lighting. Modern buildings designed for daylighting typically use 40% to 60% less electricity for lighting needs than do conventional buildings.

Sunlight and daylight are free and readily accessible. However, using sunlight without causing glare and without overheating a building can be difficult. Glare can be avoided by using window sills, walls, louvers, reflective blinds, and other devices to reflect light deep into the building. Be careful to locate windows and skylights away from the sun's direct rays to avoid overheating. For example, placing skylights on the north slope of your roof rather than on the southern exposure may reduce heat transfer. In addition, look for windows with new selective glazings that transmit the most visible light while excluding the most solar heat. For more information, see Energy efficient Windows.

Lighting Maintenance: Maintenance is vital to lighting efficiency. Light levels decrease over time because of aging lamps and dirt on fixtures, lamps, and room surfaces. Together, these factors can reduce total illumination by 50% or more, while lights continue drawing full power. The following basic maintenance suggestions help prevent this.

  • Clean fixtures, lamps, and lenses every 6 to 24 months by wiping off the dust. However, never clean an incandescent bulb while it is turned on. The water's cooling effect will shatter the hot bulb.

  • Replace lenses if they appear yellow.

  • Clean or repaint small rooms every year and larger rooms every 2 to 3 years. Dirt collects on surfaces, which reduces the amount of light they reflect.

  • Consider group relamping. Common lamps, especially incandescent and fluorescent lamps, lose 20% to 30% of their light output over their service life. Many lighting experts recommend replacing all the lamps in a lighting system at once. This saves labor, keeps illumination high, and avoids stressing any ballasts with dying lamps.

Optimizing Energy Efficiency and Lighting Quality: When making changes designed to increase the energy efficiency of lighting, it often pays to redesign the building's entire lighting system. This can improve lighting quality, make visual tasks easier, and save 50% or more on energy costs.

  • Often, you can reduce light levels without reducing light quality by following these procedures.
  • Redesign visual tasks. For example, use a better printer with darker printing.

  • Reduce light levels where there are no visual tasks. Provide the minimum light necessary for safety, security, and aesthetics.

  • Reduce light levels for visual tasks where those levels are currently excessive.

  • If you want to cut energy consumption from lighting while enhancing light quality, consider the following.
  • Establish ambient illumination at minimum acceptable levels.

  • Provide task lighting at the optimal level depending on the difficulty of visual tasks. For example, sewing requires more light than cooking.

  • Increase the efficiency of lamps, ballasts, and fixtures.

  • Improve light quality by reducing glare and brightness contrast.

  • Use daylighting where possible and practical.

Better Light, Less Cost: Using just a few of these ideas will help lower your electricity costs from lighting and make your home or workplace more comfortable and efficient.

Log in to comment
­